diff --git a/include/fmt/posix.h b/include/fmt/posix.h
index 5d1c6fa5..0e7bc646 100644
--- a/include/fmt/posix.h
+++ b/include/fmt/posix.h
@@ -1 +1,2 @@
 #include "os.h"
+#warning "fmt/posix.h is deprecated; use fmt/os.h instead"
\ No newline at end of file
diff --git a/test/CMakeLists.txt b/test/CMakeLists.txt
index 2fee2125..73919da0 100644
--- a/test/CMakeLists.txt
+++ b/test/CMakeLists.txt
@@ -125,7 +125,7 @@ if (NOT MSVC_BUILD_STATIC)
     target_compile_definitions(posix-mock-test PRIVATE FMT_LOCALE)
   endif ()
   add_test(NAME posix-mock-test COMMAND posix-mock-test)
-  add_fmt_test(posix-test)
+  add_fmt_test(os-test)
 endif ()
 
 add_fmt_executable(header-only-test
diff --git a/test/gtest-extra.h b/test/gtest-extra.h
index ee335615..3b84d448 100644
--- a/test/gtest-extra.h
+++ b/test/gtest-extra.h
@@ -10,7 +10,7 @@
 
 #include <string>
 #include "gmock.h"
-#include "fmt/posix.h"
+#include "fmt/os.h"
 
 #define FMT_TEST_THROW_(statement, expected_exception, expected_message, fail) \
   GTEST_AMBIGUOUS_ELSE_BLOCKER_                                                \
diff --git a/test/posix-test.cc b/test/os-test.cc
similarity index 99%
rename from test/posix-test.cc
rename to test/os-test.cc
index e3507e69..0accd2bc 100644
--- a/test/posix-test.cc
+++ b/test/os-test.cc
@@ -1,4 +1,4 @@
-// Formatting library for C++ - tests of the C++ interface to POSIX functions
+// Formatting library for C++ - tests of the OS-specific functionality
 //
 // Copyright (c) 2012 - present, Victor Zverovich
 // All rights reserved.
@@ -10,7 +10,6 @@
 #include <memory>
 
 #include "fmt/os.h"
-#include "fmt/posix.h"
 #include "gtest-extra.h"
 #include "util.h"
 
diff --git a/test/util.h b/test/util.h
index 7aa9da23..2282886a 100644
--- a/test/util.h
+++ b/test/util.h
@@ -9,7 +9,7 @@
 #include <cstdio>
 #include <string>
 
-#include "fmt/posix.h"
+#include "fmt/os.h"
 
 enum { BUFFER_SIZE = 256 };