diff --git a/libc/config/darwin/arm/entrypoints.txt b/libc/config/darwin/arm/entrypoints.txt
--- a/libc/config/darwin/arm/entrypoints.txt
+++ b/libc/config/darwin/arm/entrypoints.txt
@@ -105,6 +105,8 @@
     libc.src.fenv.feupdateenv
 
     # math.h entrypoints
+    libc.src.math.atanf
+    libc.src.math.atanhf
     libc.src.math.copysign
     libc.src.math.copysignf
     libc.src.math.copysignl
diff --git a/libc/config/linux/aarch64/entrypoints.txt b/libc/config/linux/aarch64/entrypoints.txt
--- a/libc/config/linux/aarch64/entrypoints.txt
+++ b/libc/config/linux/aarch64/entrypoints.txt
@@ -149,6 +149,8 @@
     libc.src.fenv.feupdateenv
 
     # math.h entrypoints
+    libc.src.math.atanf
+    libc.src.math.atanhf    
     libc.src.math.copysign
     libc.src.math.copysignf
     libc.src.math.copysignl
diff --git a/libc/config/linux/x86_64/entrypoints.txt b/libc/config/linux/x86_64/entrypoints.txt
--- a/libc/config/linux/x86_64/entrypoints.txt
+++ b/libc/config/linux/x86_64/entrypoints.txt
@@ -149,6 +149,8 @@
     libc.src.fenv.feupdateenv
 
     # math.h entrypoints
+    libc.src.math.atanf
+    libc.src.math.atanhf
     libc.src.math.copysign
     libc.src.math.copysignf
     libc.src.math.copysignl
diff --git a/libc/config/windows/entrypoints.txt b/libc/config/windows/entrypoints.txt
--- a/libc/config/windows/entrypoints.txt
+++ b/libc/config/windows/entrypoints.txt
@@ -106,6 +106,8 @@
     libc.src.fenv.feupdateenv
 
     # math.h entrypoints
+    libc.src.math.atanf    
+    libc.src.math.atanhf
     libc.src.math.copysign
     libc.src.math.copysignf
     libc.src.math.copysignl
diff --git a/libc/spec/stdc.td b/libc/spec/stdc.td
--- a/libc/spec/stdc.td
+++ b/libc/spec/stdc.td
@@ -479,6 +479,10 @@
           FunctionSpec<"coshf", RetValSpec<FloatType>, [ArgSpec<FloatType>]>,
           FunctionSpec<"sinhf", RetValSpec<FloatType>, [ArgSpec<FloatType>]>,
           FunctionSpec<"tanhf", RetValSpec<FloatType>, [ArgSpec<FloatType>]>,
+          
+          FunctionSpec<"atanf", RetValSpec<FloatType>, [ArgSpec<FloatType>]>,
+          
+          FunctionSpec<"atanhf", RetValSpec<FloatType>, [ArgSpec<FloatType>]>,
       ]
   >;
 
diff --git a/libc/src/__support/FPUtil/FPBits.h b/libc/src/__support/FPUtil/FPBits.h
--- a/libc/src/__support/FPUtil/FPBits.h
+++ b/libc/src/__support/FPUtil/FPBits.h
@@ -196,6 +196,15 @@
     }
     return result;
   }
+
+  inline static FPBits<T> create_value(bool sign, UIntType unbiased_exp,
+                                       UIntType mantissa) {
+    FPBits<T> result;
+    result.set_sign(sign);
+    result.set_unbiased_exponent(unbiased_exp);
+    result.set_mantissa(mantissa);
+    return result;
+  }
 };
 
 } // namespace fputil
diff --git a/libc/src/math/CMakeLists.txt b/libc/src/math/CMakeLists.txt
--- a/libc/src/math/CMakeLists.txt
+++ b/libc/src/math/CMakeLists.txt
@@ -66,6 +66,9 @@
     -O3
 )
 
+add_math_entrypoint_object(atanf)
+add_math_entrypoint_object(atanhf)
+
 add_math_entrypoint_object(ceil)
 add_math_entrypoint_object(ceilf)
 add_math_entrypoint_object(ceill)
diff --git a/libc/src/math/atanf.h b/libc/src/math/atanf.h
new file mode 100644
--- /dev/null
+++ b/libc/src/math/atanf.h
@@ -0,0 +1,18 @@
+//===-- Implementation header for atanf -------------------------*- C++ -*-===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_LIBC_SRC_MATH_ATANF_H
+#define LLVM_LIBC_SRC_MATH_ATANF_H
+
+namespace __llvm_libc {
+
+float atanf(float x);
+
+} // namespace __llvm_libc
+
+#endif // LLVM_LIBC_SRC_MATH_ATANF_H
diff --git a/libc/src/math/atanhf.h b/libc/src/math/atanhf.h
new file mode 100644
--- /dev/null
+++ b/libc/src/math/atanhf.h
@@ -0,0 +1,18 @@
+//===-- Implementation header for atanhf ------------------------*- C++ -*-===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_LIBC_SRC_MATH_ATANHF_H
+#define LLVM_LIBC_SRC_MATH_ATANHF_H
+
+namespace __llvm_libc {
+
+float atanhf(float x);
+
+} // namespace __llvm_libc
+
+#endif // LLVM_LIBC_SRC_MATH_ATANHF_H
diff --git a/libc/src/math/generic/CMakeLists.txt b/libc/src/math/generic/CMakeLists.txt
--- a/libc/src/math/generic/CMakeLists.txt
+++ b/libc/src/math/generic/CMakeLists.txt
@@ -1225,3 +1225,37 @@
     -O3
 )
 
+add_entrypoint_object(
+  atanhf
+  SRCS
+    atanhf.cpp
+  HDRS
+    ../atanhf.h
+  DEPENDS
+    .supfuncf
+    libc.src.__support.FPUtil.fputil
+    libc.src.__support.FPUtil.multiply_add
+    libc.src.__support.FPUtil.nearest_integer
+    libc.src.__support.FPUtil.polyeval
+    libc.include.math
+  COMPILE_OPTIONS
+    -O3
+)
+
+add_entrypoint_object(
+  atanf
+  SRCS
+    atanf.cpp
+  HDRS
+    ../atanf.h
+  DEPENDS
+    .supfuncf
+    libc.src.__support.FPUtil.fputil
+    libc.src.__support.FPUtil.multiply_add
+    libc.src.__support.FPUtil.nearest_integer
+    libc.src.__support.FPUtil.polyeval
+    libc.include.math
+  COMPILE_OPTIONS
+    -O3
+)
+
diff --git a/libc/src/math/generic/atanf.cpp b/libc/src/math/generic/atanf.cpp
new file mode 100644
--- /dev/null
+++ b/libc/src/math/generic/atanf.cpp
@@ -0,0 +1,51 @@
+//===-- Single-precision atan function ------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include "src/math/atanf.h"
+#include "math_utils.h"
+#include "src/__support/FPUtil/FPBits.h"
+#include "src/math/generic/supfuncf.h"
+
+namespace __llvm_libc {
+
+LLVM_LIBC_FUNCTION(float, atanf, (float x)) {
+  using FPBits = typename fputil::FPBits<float>;
+  FPBits xbits(x);
+  bool sign = xbits.get_sign();
+  xbits.set_sign(false);
+
+  if (unlikely(xbits.is_inf_or_nan())) {
+    if (xbits.is_inf())
+      return opt_barrier(sign ? -M_PI_2 : M_PI_2);
+    else
+      return x + 1.0f;
+  }
+
+  if (unlikely(xbits.uintval() == 0x3d8d6b23U)) {
+    if (fputil::get_round() == FE_TONEAREST) {
+      FPBits br(0x3d8d31c3U);
+      br.set_sign(sign);
+      return br.get_val();
+    }
+  }
+
+  if (unlikely(xbits.uintval() == 0x3feefcfbU)) {
+    int rounding_mode = fputil::get_round();
+    if (sign) {
+      if (rounding_mode == FE_DOWNWARD)
+        return FPBits(0xbf8a1f63U).get_val();
+    } else {
+      if (rounding_mode == FE_UPWARD)
+        return FPBits(0x3f8a1f63U).get_val();
+    }
+  }
+
+  return atan_eval(x);
+}
+
+} // namespace __llvm_libc
diff --git a/libc/src/math/generic/atanhf.cpp b/libc/src/math/generic/atanhf.cpp
new file mode 100644
--- /dev/null
+++ b/libc/src/math/generic/atanhf.cpp
@@ -0,0 +1,56 @@
+//===-- Single-precision atanh function -----------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include "src/math/atanhf.h"
+#include "src/__support/FPUtil/FPBits.h"
+#include "src/math/generic/supfuncf.h"
+
+namespace __llvm_libc {
+
+LLVM_LIBC_FUNCTION(float, atanhf, (float x)) {
+  using FPBits = typename fputil::FPBits<float>;
+  FPBits xbits(x);
+  bool sign = xbits.get_sign();
+  uint32_t x_abs = xbits.uintval() & FPBits::FloatProp::EXP_MANT_MASK;
+
+  // 0 >= 1.0
+  if (unlikely(x_abs >= 0x3F80'0000U)) {
+    if (xbits.is_nan()) {
+      return x + 1.0f;
+    }
+    if (x_abs == 0x3F80'0000U) {
+      fputil::set_except(FE_DIVBYZERO);
+      return with_errno(FPBits::inf(sign).get_val(), ERANGE);
+    } else {
+      fputil::set_except(FE_INVALID);
+      return with_errno(
+          FPBits::build_nan(1 << (fputil::MantissaWidth<float>::VALUE - 1)),
+          EDOM);
+    }
+  }
+
+  // |x| < ~0.10
+  if (unlikely(x_abs <= 0x3dcc'0000U)) {
+    // |x| <= 2^-26
+    if (unlikely(x_abs <= 0x3280'0000U)) {
+      return unlikely(x_abs == 0) ? x : (x + 0x1.5555555555555p-2 * x * x * x);
+    }
+
+    double xdbl = x;
+    double x2 = xdbl * xdbl;
+    // Pure Taylor series.
+    double pe = fputil::polyeval(x2, 0.0, 0x1.5555555555555p-2,
+                                 0x1.999999999999ap-3, 0x1.2492492492492p-3,
+                                 0x1.c71c71c71c71cp-4, 0x1.745d1745d1746p-4);
+    return fputil::multiply_add(xdbl, pe, xdbl);
+  }
+  double xdbl = x;
+  return 0.5 * log_eval((xdbl + 1.0) / (xdbl - 1.0));
+}
+
+} // namespace __llvm_libc
diff --git a/libc/src/math/generic/supfuncf.h b/libc/src/math/generic/supfuncf.h
--- a/libc/src/math/generic/supfuncf.h
+++ b/libc/src/math/generic/supfuncf.h
@@ -70,6 +70,14 @@
   double r;
 };
 
+// atan table size
+constexpr int ATAN_T_BITS = 4;
+constexpr int ATAN_T_SIZE = 1 << ATAN_T_BITS;
+
+// N[Table[ArcTan[x], {x, 1/8, 8/8, 1/8}], 40]
+extern const double ATAN_T[ATAN_T_SIZE];
+extern const double ATAN_K[5];
+
 // The function correctly calculates exp value with at least float precision
 // in range not narrow than [-log(2^-150), 90]
 template <int MULT_POWER2 = 0>
@@ -154,6 +162,63 @@
   return log2_eval(x) * 0x1.62e42fefa39efp-1;
 }
 
+// The main idea of the function is to use formula
+// atan(u) + atan(v) = atan((u+v)/(1-uv))
+
+// x should be positive, normal finite value
+inline static double atan_eval(double x) {
+  using FPB = fputil::FPBits<double>;
+  // Added some small value to umin and umax mantissa to avoid possible rounding
+  // errors.
+  FPB::UIntType umin =
+      FPB::create_value(false, FPB::EXPONENT_BIAS - ATAN_T_BITS - 1,
+                        0x100000000000UL)
+          .uintval();
+  FPB::UIntType umax =
+      FPB::create_value(false, FPB::EXPONENT_BIAS + ATAN_T_BITS,
+                        0xF000000000000UL)
+          .uintval();
+
+  FPB bs(x);
+  bool sign = bs.get_sign();
+  auto x_abs = bs.uintval() & FPB::FloatProp::EXP_MANT_MASK;
+
+  if (x_abs <= umin) {
+    double pe = __llvm_libc::fputil::polyeval(x * x, 0.0, ATAN_K[1], ATAN_K[2],
+                                              ATAN_K[3], ATAN_K[4]);
+    return fputil::multiply_add(pe, x, x);
+  }
+
+  if (x_abs >= umax) {
+    double one_over_x_m = -1.0 / x;
+    double one_over_x2 = one_over_x_m * one_over_x_m;
+    double pe = __llvm_libc::fputil::polyeval(one_over_x2, ATAN_K[0], ATAN_K[1],
+                                              ATAN_K[2], ATAN_K[3]);
+    return fputil::multiply_add(pe, one_over_x_m, sign ? (-M_PI_2) : (M_PI_2));
+  }
+
+  double pos_x = FPB(x_abs).get_val();
+  bool one_over_x = pos_x > 1.0;
+  if (one_over_x) {
+    pos_x = 1.0 / pos_x;
+  }
+
+  double near_x = fputil::nearest_integer(pos_x * ATAN_T_SIZE);
+  int val = static_cast<int>(near_x);
+  near_x *= 1.0 / ATAN_T_SIZE;
+
+  double v = (pos_x - near_x) / fputil::multiply_add(near_x, pos_x, 1.0);
+  double v2 = v * v;
+  double pe = __llvm_libc::fputil::polyeval(v2, ATAN_K[0], ATAN_K[1], ATAN_K[2],
+                                            ATAN_K[3], ATAN_K[4]);
+  double result;
+  if (one_over_x)
+    result = M_PI_2 - fputil::multiply_add(pe, v, ATAN_T[val - 1]);
+  else
+    result = fputil::multiply_add(pe, v, ATAN_T[val - 1]);
+  return sign ? -result : result;
+}
+
 } // namespace __llvm_libc
 
 #endif // LLVM_LIBC_SRC_MATH_GENERIC_EXPLOGXF_H
diff --git a/libc/src/math/generic/supfuncf.cpp b/libc/src/math/generic/supfuncf.cpp
--- a/libc/src/math/generic/supfuncf.cpp
+++ b/libc/src/math/generic/supfuncf.cpp
@@ -86,4 +86,19 @@
     double K_LOG2_EVEN[4] = {-0x1.71547652b82fep-1, -0x1.71547652b82fep-2,
                              -0x1.ec709dc3a03fdp-3, -0x1.2776c50ef9bfep-3};
 
+// N[Table[ArcTan[x], {x, 1/16, 16/16, 1/16}], 40]
+alignas(64) const double ATAN_T[ATAN_T_SIZE] = {
+    0x1.ff55bb72cfdeap-5, 0x1.fd5ba9aac2f6ep-4, 0x1.7b97b4bce5b02p-3,
+    0x1.f5b75f92c80ddp-3, 0x1.362773707ebccp-2, 0x1.6f61941e4def1p-2,
+    0x1.a64eec3cc23fdp-2, 0x1.dac670561bb4fp-2, 0x1.0657e94db30d0p-1,
+    0x1.1e00babdefeb4p-1, 0x1.345f01cce37bbp-1, 0x1.4978fa3269ee1p-1,
+    0x1.5d58987169b18p-1, 0x1.700a7c5784634p-1, 0x1.819d0b7158a4dp-1,
+    0x1.921fb54442d18p-1};
+
+// for(int i = 0; i < 5; i++)
+//     printf("%.13a,\n", (-2 * (i % 2) + 1) * 1.0 / (2 * i + 1));
+alignas(64) const double ATAN_K[5] = {
+    0x1.0000000000000p+0, -0x1.5555555555555p-2, 0x1.999999999999ap-3,
+    -0x1.2492492492492p-3, 0x1.c71c71c71c71cp-4};
+
 } // namespace __llvm_libc
diff --git a/libc/test/src/math/CMakeLists.txt b/libc/test/src/math/CMakeLists.txt
--- a/libc/test/src/math/CMakeLists.txt
+++ b/libc/test/src/math/CMakeLists.txt
@@ -1374,6 +1374,30 @@
     libc.src.__support.FPUtil.fputil
 )
 
+add_fp_unittest(
+  atanhf_test
+  NEED_MPFR
+  SUITE
+    libc_math_unittests
+  SRCS
+    atanhf_test.cpp
+  DEPENDS
+    libc.src.math.atanhf
+    libc.src.__support.FPUtil.fputil
+)
+
+add_fp_unittest(
+  atanf_test
+  NEED_MPFR
+  SUITE
+    libc_math_unittests
+  SRCS
+    atanf_test.cpp
+  DEPENDS
+    libc.src.math.atanf
+    libc.src.__support.FPUtil.fputil
+)
+
 add_subdirectory(generic)
 add_subdirectory(exhaustive)
 add_subdirectory(differential_testing)
diff --git a/libc/test/src/math/atanf_test.cpp b/libc/test/src/math/atanf_test.cpp
new file mode 100644
--- /dev/null
+++ b/libc/test/src/math/atanf_test.cpp
@@ -0,0 +1,65 @@
+//===-- Unittests for atanf -----------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include "src/__support/FPUtil/FPBits.h"
+#include "src/math/atanf.h"
+#include "utils/MPFRWrapper/MPFRUtils.h"
+#include "utils/UnitTest/FPMatcher.h"
+#include "utils/UnitTest/Test.h"
+#include <math.h>
+
+#include <errno.h>
+#include <stdint.h>
+
+#include <initializer_list>
+
+using FPBits = __llvm_libc::fputil::FPBits<float>;
+
+namespace mpfr = __llvm_libc::testing::mpfr;
+
+DECLARE_SPECIAL_CONSTANTS(float)
+
+TEST(LlvmLibcAtanfTest, SpecialNumbers) {
+  errno = 0;
+  __llvm_libc::fputil::clear_except(FE_ALL_EXCEPT);
+  EXPECT_FP_EQ(aNaN, __llvm_libc::atanf(aNaN));
+  EXPECT_FP_EXCEPTION(FE_INVALID);
+  EXPECT_MATH_ERRNO(0);
+
+  __llvm_libc::fputil::clear_except(FE_ALL_EXCEPT);
+  EXPECT_FP_EQ(0.0f, __llvm_libc::atanf(0.0f));
+  EXPECT_FP_EXCEPTION(0);
+  EXPECT_MATH_ERRNO(0);
+
+  __llvm_libc::fputil::clear_except(FE_ALL_EXCEPT);
+  EXPECT_FP_EQ(-0.0f, __llvm_libc::atanf(-0.0f));
+  EXPECT_FP_EXCEPTION(0);
+  EXPECT_MATH_ERRNO(0);
+}
+
+TEST(LlvmLibcAtanfTest, InFloatRange) {
+  constexpr uint32_t COUNT = 1000000;
+  const uint32_t STEP = FPBits(inf).uintval() / COUNT;
+  for (uint32_t i = 0, v = 0; i <= COUNT; ++i, v += STEP) {
+    float x = float(FPBits(v));
+    EXPECT_MPFR_MATCH_ALL_ROUNDING(mpfr::Operation::Atan, x,
+                                   __llvm_libc::atanf(x), 0.5);
+    EXPECT_MPFR_MATCH_ALL_ROUNDING(mpfr::Operation::Atan, -x,
+                                   __llvm_libc::atanf(-x), 0.5);
+  }
+}
+
+// For small values, tanh(x) is x.
+TEST(LlvmLibcAtanfTest, SpecialValues) {
+  for (uint32_t v : {0x3d8d6b23U, 0x3feefcfbU, 0xbd8d6b23U, 0xbfeefcfbU,
+                     0x7F800000U, 0xFF800000U}) {
+    float x = float(FPBits(v));
+    EXPECT_MPFR_MATCH_ALL_ROUNDING(mpfr::Operation::Atan, x,
+                                   __llvm_libc::atanf(x), 0.5);
+  }
+}
diff --git a/libc/test/src/math/atanhf_test.cpp b/libc/test/src/math/atanhf_test.cpp
new file mode 100644
--- /dev/null
+++ b/libc/test/src/math/atanhf_test.cpp
@@ -0,0 +1,108 @@
+//===-- Unittests for atanhf ----------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include "src/__support/FPUtil/FPBits.h"
+#include "src/math/atanhf.h"
+#include "utils/MPFRWrapper/MPFRUtils.h"
+#include "utils/UnitTest/FPMatcher.h"
+#include "utils/UnitTest/Test.h"
+#include <math.h>
+
+#include <errno.h>
+#include <stdint.h>
+
+using FPBits = __llvm_libc::fputil::FPBits<float>;
+
+namespace mpfr = __llvm_libc::testing::mpfr;
+
+DECLARE_SPECIAL_CONSTANTS(float)
+
+TEST(LlvmLibcAtanhfTest, SpecialNumbers) {
+  errno = 0;
+  __llvm_libc::fputil::clear_except(FE_ALL_EXCEPT);
+  EXPECT_FP_EQ(aNaN, __llvm_libc::atanhf(aNaN));
+  EXPECT_FP_EXCEPTION(FE_INVALID);
+  EXPECT_MATH_ERRNO(0);
+
+  __llvm_libc::fputil::clear_except(FE_ALL_EXCEPT);
+  EXPECT_FP_EQ(0.0f, __llvm_libc::atanhf(0.0f));
+  EXPECT_FP_EXCEPTION(0);
+  EXPECT_MATH_ERRNO(0);
+
+  __llvm_libc::fputil::clear_except(FE_ALL_EXCEPT);
+  EXPECT_FP_EQ(-0.0f, __llvm_libc::atanhf(-0.0f));
+  EXPECT_FP_EXCEPTION(0);
+  EXPECT_MATH_ERRNO(0);
+
+  __llvm_libc::fputil::clear_except(FE_ALL_EXCEPT);
+  EXPECT_FP_EQ(inf, __llvm_libc::atanhf(1.0f));
+  EXPECT_FP_EXCEPTION(FE_DIVBYZERO);
+  EXPECT_MATH_ERRNO(ERANGE);
+
+  __llvm_libc::fputil::clear_except(FE_ALL_EXCEPT);
+  EXPECT_FP_EQ(neg_inf, __llvm_libc::atanhf(-1.0f));
+  EXPECT_FP_EXCEPTION(FE_DIVBYZERO);
+  EXPECT_MATH_ERRNO(ERANGE);
+
+  auto bt = FPBits(1.0f);
+  bt.bits += 1;
+
+  __llvm_libc::fputil::clear_except(FE_ALL_EXCEPT);
+  EXPECT_FP_EQ(aNaN, __llvm_libc::atanhf(bt.get_val()));
+  EXPECT_FP_EXCEPTION(FE_INVALID);
+  EXPECT_MATH_ERRNO(EDOM);
+
+  __llvm_libc::fputil::clear_except(FE_ALL_EXCEPT);
+  bt.set_sign(true);
+  EXPECT_FP_EQ(aNaN, __llvm_libc::atanhf(bt.get_val()));
+  EXPECT_FP_EXCEPTION(FE_INVALID);
+  EXPECT_MATH_ERRNO(EDOM);
+
+  __llvm_libc::fputil::clear_except(FE_ALL_EXCEPT);
+  EXPECT_FP_EQ(aNaN, __llvm_libc::atanhf(2.0f));
+  EXPECT_FP_EXCEPTION(FE_INVALID);
+  EXPECT_MATH_ERRNO(EDOM);
+
+  __llvm_libc::fputil::clear_except(FE_ALL_EXCEPT);
+  EXPECT_FP_EQ(aNaN, __llvm_libc::atanhf(-2.0f));
+  EXPECT_FP_EXCEPTION(FE_INVALID);
+  EXPECT_MATH_ERRNO(EDOM);
+
+  __llvm_libc::fputil::clear_except(FE_ALL_EXCEPT);
+  EXPECT_FP_EQ(aNaN, __llvm_libc::atanhf(inf));
+  EXPECT_FP_EXCEPTION(FE_INVALID);
+  EXPECT_MATH_ERRNO(EDOM);
+
+  bt.set_sign(true);
+  EXPECT_FP_EQ(aNaN, __llvm_libc::atanhf(neg_inf));
+  EXPECT_FP_EXCEPTION(FE_INVALID);
+  EXPECT_MATH_ERRNO(EDOM);
+}
+
+TEST(LlvmLibcAtanhfTest, InFloatRange) {
+  constexpr uint32_t COUNT = 1000000;
+  const uint32_t STEP = FPBits(1.0f).uintval() / COUNT;
+  for (uint32_t i = 0, v = 0; i <= COUNT; ++i, v += STEP) {
+    float x = float(FPBits(v));
+    ASSERT_MPFR_MATCH(mpfr::Operation::Atanh, x, __llvm_libc::atanhf(x), 0.5);
+    ASSERT_MPFR_MATCH(mpfr::Operation::Atanh, -x, __llvm_libc::atanhf(-x), 0.5);
+  }
+}
+
+// For small values, tanh(x) is x.
+TEST(LlvmLibcAtanhfTest, SmallValues) {
+  float x = float(FPBits(uint32_t(0x17800000)));
+  float result = __llvm_libc::atanhf(x);
+  EXPECT_MPFR_MATCH(mpfr::Operation::Atanh, x, result, 0.5);
+  EXPECT_FP_EQ(x, result);
+
+  x = float(FPBits(uint32_t(0x00400000)));
+  result = __llvm_libc::atanhf(x);
+  EXPECT_MPFR_MATCH(mpfr::Operation::Atanh, x, result, 0.5);
+  EXPECT_FP_EQ(x, result);
+}
diff --git a/libc/test/src/math/exhaustive/CMakeLists.txt b/libc/test/src/math/exhaustive/CMakeLists.txt
--- a/libc/test/src/math/exhaustive/CMakeLists.txt
+++ b/libc/test/src/math/exhaustive/CMakeLists.txt
@@ -291,3 +291,37 @@
     -lpthread
 )
 
+add_fp_unittest(
+  atanhf_test
+  NO_RUN_POSTBUILD
+  NEED_MPFR
+  SUITE
+    libc_math_exhaustive_tests
+  SRCS
+    atanhf_test.cpp
+  DEPENDS
+    .exhaustive_test
+    libc.include.math
+    libc.src.math.atanhf
+    libc.src.__support.FPUtil.fputil
+  LINK_LIBRARIES
+    -lpthread
+)
+
+add_fp_unittest(
+  atanf_test
+  NO_RUN_POSTBUILD
+  NEED_MPFR
+  SUITE
+    libc_math_exhaustive_tests
+  SRCS
+    atanf_test.cpp
+  DEPENDS
+    .exhaustive_test
+    libc.include.math
+    libc.src.math.atanf
+    libc.src.__support.FPUtil.fputil
+  LINK_LIBRARIES
+    -lpthread
+)
+
diff --git a/libc/test/src/math/exhaustive/atanf_test.cpp b/libc/test/src/math/exhaustive/atanf_test.cpp
new file mode 100644
--- /dev/null
+++ b/libc/test/src/math/exhaustive/atanf_test.cpp
@@ -0,0 +1,76 @@
+//===-- Exhaustive test for atanf -----------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include "exhaustive_test.h"
+#include "src/__support/FPUtil/FPBits.h"
+#include "src/math/atanf.h"
+#include "utils/MPFRWrapper/MPFRUtils.h"
+
+#include <thread>
+
+using FPBits = __llvm_libc::fputil::FPBits<float>;
+
+namespace mpfr = __llvm_libc::testing::mpfr;
+
+struct LlvmLibcAtanfExhaustiveTest : public LlvmLibcExhaustiveTest<uint32_t> {
+  bool check(uint32_t start, uint32_t stop,
+             mpfr::RoundingMode rounding) override {
+    mpfr::ForceRoundingMode r(rounding);
+    uint32_t bits = start;
+    bool result = true;
+    do {
+      FPBits xbits(bits);
+      float x = float(xbits);
+      result &= EXPECT_MPFR_MATCH(mpfr::Operation::Atan, x,
+                                  __llvm_libc::atanf(x), 0.5, rounding);
+    } while (bits++ < stop);
+    return result;
+  }
+};
+
+static const int NUM_THREADS = std::thread::hardware_concurrency();
+
+// Range: [0, 1.0];
+static const uint32_t POS_START = 0x0000'0000U;
+static const uint32_t POS_STOP = FPBits::inf().uintval();
+
+TEST_F(LlvmLibcAtanfExhaustiveTest, PostiveRangeRoundNearestTieToEven) {
+  test_full_range(POS_START, POS_STOP, mpfr::RoundingMode::Nearest);
+}
+
+TEST_F(LlvmLibcAtanfExhaustiveTest, PostiveRangeRoundUp) {
+  test_full_range(POS_START, POS_STOP, mpfr::RoundingMode::Upward);
+}
+
+TEST_F(LlvmLibcAtanfExhaustiveTest, PostiveRangeRoundDown) {
+  test_full_range(POS_START, POS_STOP, mpfr::RoundingMode::Downward);
+}
+
+TEST_F(LlvmLibcAtanfExhaustiveTest, PostiveRangeRoundTowardZero) {
+  test_full_range(POS_START, POS_STOP, mpfr::RoundingMode::TowardZero);
+}
+
+// Range: [-1.0, 0];
+static const uint32_t NEG_START = 0x8000'0000U;
+static const uint32_t NEG_STOP = FPBits::neg_inf().uintval();
+
+TEST_F(LlvmLibcAtanfExhaustiveTest, NegativeRangeRoundNearestTieToEven) {
+  test_full_range(NEG_START, NEG_STOP, mpfr::RoundingMode::Nearest);
+}
+
+TEST_F(LlvmLibcAtanfExhaustiveTest, NegativeRangeRoundUp) {
+  test_full_range(NEG_START, NEG_STOP, mpfr::RoundingMode::Upward);
+}
+
+TEST_F(LlvmLibcAtanfExhaustiveTest, NegativeRangeRoundDown) {
+  test_full_range(NEG_START, NEG_STOP, mpfr::RoundingMode::Downward);
+}
+
+TEST_F(LlvmLibcAtanfExhaustiveTest, NegativeRangeRoundTowardZero) {
+  test_full_range(NEG_START, NEG_STOP, mpfr::RoundingMode::TowardZero);
+}
diff --git a/libc/test/src/math/exhaustive/atanhf_test.cpp b/libc/test/src/math/exhaustive/atanhf_test.cpp
new file mode 100644
--- /dev/null
+++ b/libc/test/src/math/exhaustive/atanhf_test.cpp
@@ -0,0 +1,76 @@
+//===-- Exhaustive test for atanhf ----------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include "exhaustive_test.h"
+#include "src/__support/FPUtil/FPBits.h"
+#include "src/math/atanhf.h"
+#include "utils/MPFRWrapper/MPFRUtils.h"
+
+#include <thread>
+
+using FPBits = __llvm_libc::fputil::FPBits<float>;
+
+namespace mpfr = __llvm_libc::testing::mpfr;
+
+struct LlvmLibcAtanhfExhaustiveTest : public LlvmLibcExhaustiveTest<uint32_t> {
+  bool check(uint32_t start, uint32_t stop,
+             mpfr::RoundingMode rounding) override {
+    mpfr::ForceRoundingMode r(rounding);
+    uint32_t bits = start;
+    bool result = true;
+    do {
+      FPBits xbits(bits);
+      float x = float(xbits);
+      result &= EXPECT_MPFR_MATCH(mpfr::Operation::Atanh, x,
+                                  __llvm_libc::atanhf(x), 0.5, rounding);
+    } while (bits++ < stop);
+    return result;
+  }
+};
+
+static const int NUM_THREADS = std::thread::hardware_concurrency();
+
+// Range: [0, 1.0];
+static const uint32_t POS_START = 0x0000'0000U;
+static const uint32_t POS_STOP = FPBits(1.0f).uintval();
+
+TEST_F(LlvmLibcAtanhfExhaustiveTest, PostiveRangeRoundNearestTieToEven) {
+  test_full_range(POS_START, POS_STOP, mpfr::RoundingMode::Nearest);
+}
+
+TEST_F(LlvmLibcAtanhfExhaustiveTest, PostiveRangeRoundUp) {
+  test_full_range(POS_START, POS_STOP, mpfr::RoundingMode::Upward);
+}
+
+TEST_F(LlvmLibcAtanhfExhaustiveTest, PostiveRangeRoundDown) {
+  test_full_range(POS_START, POS_STOP, mpfr::RoundingMode::Downward);
+}
+
+TEST_F(LlvmLibcAtanhfExhaustiveTest, PostiveRangeRoundTowardZero) {
+  test_full_range(POS_START, POS_STOP, mpfr::RoundingMode::TowardZero);
+}
+
+// Range: [-1.0, 0];
+static const uint32_t NEG_START = 0x8000'0000U;
+static const uint32_t NEG_STOP = FPBits(-1.0f).uintval();
+
+TEST_F(LlvmLibcAtanhfExhaustiveTest, NegativeRangeRoundNearestTieToEven) {
+  test_full_range(NEG_START, NEG_STOP, mpfr::RoundingMode::Nearest);
+}
+
+TEST_F(LlvmLibcAtanhfExhaustiveTest, NegativeRangeRoundUp) {
+  test_full_range(NEG_START, NEG_STOP, mpfr::RoundingMode::Upward);
+}
+
+TEST_F(LlvmLibcAtanhfExhaustiveTest, NegativeRangeRoundDown) {
+  test_full_range(NEG_START, NEG_STOP, mpfr::RoundingMode::Downward);
+}
+
+TEST_F(LlvmLibcAtanhfExhaustiveTest, NegativeRangeRoundTowardZero) {
+  test_full_range(NEG_START, NEG_STOP, mpfr::RoundingMode::TowardZero);
+}
diff --git a/libc/test/src/math/supfuncf_test.cpp b/libc/test/src/math/supfuncf_test.cpp
--- a/libc/test/src/math/supfuncf_test.cpp
+++ b/libc/test/src/math/supfuncf_test.cpp
@@ -31,9 +31,10 @@
       if (v > ustop)                                                           \
         break;                                                                 \
       float x = FPBits(uint32_t(v)).get_val();                                 \
-      if ((f_check)(x))                                                        \
+      if ((f_check)(x)) {                                                      \
         EXPECT_MPFR_MATCH_ALL_ROUNDING(mfp_op, x, static_cast<float>((f)(x)),  \
                                        (prec));                                \
+      }                                                                        \
     }                                                                          \
   }
 
@@ -69,3 +70,13 @@
   CHECK_DATA(0.0f, inf, mpfr::Operation::Log, __llvm_libc::log_eval, isnormal,
              def_count, def_prec);
 }
+
+TEST(LlvmLibcAtanfPosTest, InFloatRange) {
+  CHECK_DATA(0.0f, inf, mpfr::Operation::Atan, __llvm_libc::atan_eval, isfinite,
+             def_count, def_prec);
+}
+
+TEST(LlvmLibcAtanfNegTest, InFloatRange) {
+  CHECK_DATA(-0.0f, neg_inf, mpfr::Operation::Atan, __llvm_libc::atan_eval,
+             isfinite, def_count, def_prec);
+}
diff --git a/libc/utils/MPFRWrapper/MPFRUtils.h b/libc/utils/MPFRWrapper/MPFRUtils.h
--- a/libc/utils/MPFRWrapper/MPFRUtils.h
+++ b/libc/utils/MPFRWrapper/MPFRUtils.h
@@ -25,6 +25,8 @@
   // and output floating point numbers are of the same kind.
   BeginUnaryOperationsSingleOutput,
   Abs,
+  Atan,
+  Atanh,
   Ceil,
   Cos,
   Cosh,
diff --git a/libc/utils/MPFRWrapper/MPFRUtils.cpp b/libc/utils/MPFRWrapper/MPFRUtils.cpp
--- a/libc/utils/MPFRWrapper/MPFRUtils.cpp
+++ b/libc/utils/MPFRWrapper/MPFRUtils.cpp
@@ -182,6 +182,18 @@
     return result;
   }
 
+  MPFRNumber atan() const {
+    MPFRNumber result(*this);
+    mpfr_atan(result.value, value, mpfr_rounding);
+    return result;
+  }
+
+  MPFRNumber atanh() const {
+    MPFRNumber result(*this);
+    mpfr_atanh(result.value, value, mpfr_rounding);
+    return result;
+  }
+
   MPFRNumber ceil() const {
     MPFRNumber result(*this);
     mpfr_ceil(result.value, value);
@@ -500,6 +512,10 @@
   switch (op) {
   case Operation::Abs:
     return mpfrInput.abs();
+  case Operation::Atan:
+    return mpfrInput.atan();
+  case Operation::Atanh:
+    return mpfrInput.atanh();
   case Operation::Ceil:
     return mpfrInput.ceil();
   case Operation::Cos: