diff --git a/contrib/seekable_format/examples/parallel_processing.c b/contrib/seekable_format/examples/parallel_processing.c
index 356561e5a..928371025 100644
--- a/contrib/seekable_format/examples/parallel_processing.c
+++ b/contrib/seekable_format/examples/parallel_processing.c
@@ -19,7 +19,7 @@
 #define ZSTD_STATIC_LINKING_ONLY
 #include <zstd.h>      // presumes zstd library is installed
 #include <zstd_errors.h>
-#if defined(WIN32) || defined(_WIN32)
+#if defined(_WIN32)
 #  include <windows.h>
 #  define SLEEP(x) Sleep(x)
 #else
diff --git a/programs/fileio.c b/programs/fileio.c
index 217232542..81d343023 100644
--- a/programs/fileio.c
+++ b/programs/fileio.c
@@ -527,7 +527,7 @@ static int FIO_removeFile(const char* path)
         DISPLAYLEVEL(2, "zstd: Refusing to remove non-regular file %s\n", path);
         return 0;
     }
-#if defined(_WIN32) || defined(WIN32)
+#if defined(_WIN32)
     /* windows doesn't allow remove read-only files,
      * so try to make it writable first */
     if (!(statbuf.st_mode & _S_IWRITE)) {
diff --git a/programs/platform.h b/programs/platform.h
index 43c5dc969..bbe0965ae 100644
--- a/programs/platform.h
+++ b/programs/platform.h
@@ -141,7 +141,7 @@ extern "C" {
 #elif defined(MSDOS) || defined(OS2)
 #  include <io.h>       /* _isatty */
 #  define IS_CONSOLE(stdStream) _isatty(_fileno(stdStream))
-#elif defined(WIN32) || defined(_WIN32)
+#elif defined(_WIN32)
 #  include <io.h>      /* _isatty */
 #  include <windows.h> /* DeviceIoControl, HANDLE, FSCTL_SET_SPARSE */
 #  include <stdio.h>   /* FILE */
@@ -157,7 +157,7 @@ static __inline int IS_CONSOLE(FILE* stdStream) {
 /******************************
 *  OS-specific IO behaviors
 ******************************/
-#if defined(MSDOS) || defined(OS2) || defined(WIN32) || defined(_WIN32)
+#if defined(MSDOS) || defined(OS2) || defined(_WIN32)
 #  include <fcntl.h>   /* _O_BINARY */
 #  include <io.h>      /* _setmode, _fileno, _get_osfhandle */
 #  if !defined(__DJGPP__)
diff --git a/programs/util.h b/programs/util.h
index 8234646bf..571d39421 100644
--- a/programs/util.h
+++ b/programs/util.h
@@ -338,7 +338,7 @@ void UTIL_refFilename(FileNamesTable* fnt, const char* filename);
 FileNamesTable*
 UTIL_createExpandedFNT(const char* const* filenames, size_t nbFilenames, int followLinks);
 
-#if defined(_WIN32) || defined(WIN32)
+#if defined(_WIN32)
 DWORD CountSetBits(ULONG_PTR bitMask);
 #endif
 
diff --git a/zlibWrapper/examples/minigzip.c b/zlibWrapper/examples/minigzip.c
index 717a94df9..67a17907b 100644
--- a/zlibWrapper/examples/minigzip.c
+++ b/zlibWrapper/examples/minigzip.c
@@ -34,7 +34,7 @@
 #  include <sys/stat.h>
 #endif
 
-#if defined(MSDOS) || defined(OS2) || defined(WIN32) || defined(__CYGWIN__)
+#if defined(MSDOS) || defined(OS2) || defined(_WIN32) || defined(__CYGWIN__)
 #  include <fcntl.h>
 #  include <io.h>
 #  ifdef UNDER_CE
@@ -63,7 +63,7 @@
 #endif
 
 #if !defined(Z_HAVE_UNISTD_H) && !defined(_LARGEFILE64_SOURCE)
-#ifndef WIN32 /* unlink already in stdio.h for WIN32 */
+#ifndef _WIN32 /* unlink already in stdio.h for WIN32 */
   extern int unlink _Z_OF((const char *));
 #endif
 #endif