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
@@ -18,6 +18,9 @@
     # errno.h entrypoints
     libc.src.errno.__errno_location
 
+    # stdlib.h entrypoints
+    libc.src.stdlib.abs
+
     # string.h entrypoints
     libc.src.string.bzero
     libc.src.string.memchr
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
@@ -34,6 +34,7 @@
     # stdlib.h entrypoints
     libc.src.stdlib._Exit
     libc.src.stdlib.abort
+    libc.src.stdlib.abs
 
     # string.h entrypoints
     libc.src.string.bzero
diff --git a/libc/spec/stdc.td b/libc/spec/stdc.td
--- a/libc/spec/stdc.td
+++ b/libc/spec/stdc.td
@@ -353,6 +353,7 @@
       [], // Enumerations
       [
           FunctionSpec<"abort", RetValSpec<NoReturn>, [ArgSpec<VoidType>]>,
+          FunctionSpec<"abs", RetValSpec<IntType>, [ArgSpec<IntType>]>,
           FunctionSpec<"_Exit", RetValSpec<NoReturn>, [ArgSpec<IntType>]>,
       ]
   >;
diff --git a/libc/src/stdlib/CMakeLists.txt b/libc/src/stdlib/CMakeLists.txt
--- a/libc/src/stdlib/CMakeLists.txt
+++ b/libc/src/stdlib/CMakeLists.txt
@@ -20,3 +20,11 @@
     libc.src.signal.raise
     ._Exit
 )
+
+add_entrypoint_object(
+  abs
+  SRCS
+    abs.cpp
+  HDRS
+    abs.h
+)
diff --git a/libc/src/stdlib/abs.h b/libc/src/stdlib/abs.h
new file mode 100644
--- /dev/null
+++ b/libc/src/stdlib/abs.h
@@ -0,0 +1,18 @@
+//===-- Implementation header for abs ---------------------------*- 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_STDLIB_ABS_H
+#define LLVM_LIBC_SRC_STDLIB_ABS_H
+
+namespace __llvm_libc {
+
+int abs(int n);
+
+} // namespace __llvm_libc
+
+#endif // LLVM_LIBC_SRC_STDLIB_ABS_H
\ No newline at end of file
diff --git a/libc/src/stdlib/abs.cpp b/libc/src/stdlib/abs.cpp
new file mode 100644
--- /dev/null
+++ b/libc/src/stdlib/abs.cpp
@@ -0,0 +1,20 @@
+//===-- Implementation of abs ---------------------------------------------===//
+//
+// 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/stdlib/abs.h"
+#include "src/__support/common.h"
+
+namespace __llvm_libc {
+
+int LLVM_LIBC_ENTRYPOINT(abs)(int n) {
+  if (n < 0)
+    return -n;
+  return n;
+}
+
+} // namespace __llvm_libc
\ No newline at end of file
diff --git a/libc/test/src/stdlib/CMakeLists.txt b/libc/test/src/stdlib/CMakeLists.txt
--- a/libc/test/src/stdlib/CMakeLists.txt
+++ b/libc/test/src/stdlib/CMakeLists.txt
@@ -24,3 +24,13 @@
     libc.src.stdlib._Exit
     libc.src.signal.raise
 )
+
+add_libc_unittest(
+  abs_test
+  SUITE
+    libc_stdlib_unittests
+  SRCS
+    abs_test.cpp
+  DEPENDS
+    libc.src.stdlib.abs
+)
diff --git a/libc/test/src/stdlib/abs_test.cpp b/libc/test/src/stdlib/abs_test.cpp
new file mode 100644
--- /dev/null
+++ b/libc/test/src/stdlib/abs_test.cpp
@@ -0,0 +1,16 @@
+//===-- Unittests for abs -------------------------------------------------===//
+//
+// 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/stdlib/abs.h"
+#include "utils/UnitTest/Test.h"
+
+TEST(AbsTest, Zero) { EXPECT_EQ(__llvm_libc::abs(0), 0); }
+
+TEST(AbsTest, Positive) { EXPECT_EQ(__llvm_libc::abs(1), 1); }
+
+TEST(AbsTest, Negative) { EXPECT_EQ(__llvm_libc::abs(-1), 1); }