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
@@ -26,6 +26,7 @@
     libc.src.string.strcpy
     libc.src.string.strcat
     libc.src.string.strlen
+    libc.src.string.strcmp
 
     # sys/mman.h entrypoints
     libc.src.sys.mman.mmap
diff --git a/libc/src/string/CMakeLists.txt b/libc/src/string/CMakeLists.txt
--- a/libc/src/string/CMakeLists.txt
+++ b/libc/src/string/CMakeLists.txt
@@ -34,6 +34,16 @@
     libc.include.string
 )
 
+add_entrypoint_object(
+  strcmp
+  SRCS
+    strcmp.cpp
+  HDRS
+    strcmp.h
+  DEPENDS
+    libc.include.string
+)
+
 # Helper to define a function with multiple implementations
 # - Computes flags to satisfy required/rejected features and arch,
 # - Declares an entry point,
diff --git a/libc/src/string/strcmp.h b/libc/src/string/strcmp.h
new file mode 100644
--- /dev/null
+++ b/libc/src/string/strcmp.h
@@ -0,0 +1,20 @@
+//===-- Implementation header for strcmp ------------------------*- 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_STRING_STRCMP_H
+#define LLVM_LIBC_SRC_STRING_STRCMP_H
+
+#include "include/string.h"
+
+namespace __llvm_libc {
+
+int strcmp(const char *l, const char *r);
+
+} // namespace __llvm_libc
+
+#endif // LLVM_LIBC_SRC_STRING_STRCMP_H
diff --git a/libc/src/string/strcmp.cpp b/libc/src/string/strcmp.cpp
new file mode 100644
--- /dev/null
+++ b/libc/src/string/strcmp.cpp
@@ -0,0 +1,25 @@
+//===-- Implementation of strcmp ------------------------------------------===//
+//
+// 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/string/strcmp.h"
+
+#include "src/__support/common.h"
+
+namespace __llvm_libc {
+
+int LLVM_LIBC_ENTRYPOINT(strcmp)(const char *l, const char *r) {
+  while (*l) {
+    if (*l != *r)
+      break;
+    ++l;
+    ++r;
+  }
+  return *(const unsigned char *)l - *(const unsigned char *)r;
+}
+
+} // namespace __llvm_libc
diff --git a/libc/test/src/string/CMakeLists.txt b/libc/test/src/string/CMakeLists.txt
--- a/libc/test/src/string/CMakeLists.txt
+++ b/libc/test/src/string/CMakeLists.txt
@@ -32,6 +32,16 @@
     libc.src.string.strlen
 )
 
+add_libc_unittest(
+  strcmp_test
+  SUITE
+    libc_string_unittests
+  SRCS
+    strcmp_test.cpp
+  DEPENDS
+    libc.src.string.strcmp
+)
+
 # Tests all implementations that can run on the host.
 function(add_libc_multi_impl_test name)
   get_property(fq_implementations GLOBAL PROPERTY ${name}_implementations)
diff --git a/libc/test/src/string/strcmp_test.cpp b/libc/test/src/string/strcmp_test.cpp
new file mode 100644
--- /dev/null
+++ b/libc/test/src/string/strcmp_test.cpp
@@ -0,0 +1,74 @@
+//===-- Unittests for strcmp ----------------------------------------------===//
+//
+// 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/string/strcmp.h"
+#include "utils/UnitTest/Test.h"
+
+TEST(StrCmpTest, EmptyStringsShouldReturnZero) {
+  const char *s1 = "";
+  const char *s2 = "";
+  const int result = __llvm_libc::strcmp(s1, s2);
+  ASSERT_EQ(result, 0);
+}
+
+TEST(StrCmpTest, EmptyStringShouldNotEqualNonEmptyString) {
+  const char *empty = "";
+  const char *s2 = "abc";
+  int result = __llvm_libc::strcmp(empty, s2);
+  // This should be '\0' - 'a' = -97
+  ASSERT_EQ(result, -97);
+
+  // Similar case if empty string is second argument.
+  const char *s3 = "123";
+  result = __llvm_libc::strcmp(s3, empty);
+  // This should be '1' - '\0' = 49
+  ASSERT_EQ(result, 49);
+}
+
+TEST(StrCmpTest, EqualStringsShouldReturnZero) {
+  const char *s1 = "abc";
+  const char *s2 = "abc";
+  const int result = __llvm_libc::strcmp(s1, s2);
+  ASSERT_EQ(result, 0);
+}
+
+TEST(StrCmpTest, ShouldReturnResultOfFirstDifference) {
+  const char *s1 = "___B42__";
+  const char *s2 = "___C55__";
+  const int result = __llvm_libc::strcmp(s1, s2);
+  // This should return 'B' - 'C' = -1.
+  ASSERT_EQ(result, -1);
+}
+
+TEST(StrCmpTest, CapitalizedLetterShouldNotBeEqual) {
+  const char *s1 = "abcd";
+  const char *s2 = "abCd";
+  const int result = __llvm_libc::strcmp(s1, s2);
+  // 'c' - 'C' = 32.
+  ASSERT_EQ(result, 32);
+}
+
+TEST(StrCmpTest, UnequalLengthStringsShouldNotReturnZero) {
+  const char *s1 = "abc";
+  const char *s2 = "abcd";
+  const int result = __llvm_libc::strcmp(s1, s2);
+  // '\0' - 'd' = -100.
+  ASSERT_EQ(result, -100);
+}
+
+TEST(StrCmpTest, StringArgumentSwapChangesSign) {
+  const char *a = "a";
+  const char *b = "b";
+  int result = __llvm_libc::strcmp(b, a);
+  // 'b' - 'a' = 1.
+  ASSERT_EQ(result, 1);
+
+  result = __llvm_libc::strcmp(a, b);
+  // 'a' - 'b' = -1.
+  ASSERT_EQ(result, -1);
+}