diff --git a/include/ruby/win32.h b/include/ruby/win32.h
index 197eb8a802..18de3a17d8 100644
--- a/include/ruby/win32.h
+++ b/include/ruby/win32.h
@@ -125,8 +125,15 @@ typedef unsigned int uintptr_t;
 #define O_SHARE_DELETE 0x20000000 /* for rb_w32_open(), rb_w32_wopen() */
 
 typedef int clockid_t;
+#if defined(__MINGW32__)
+#undef CLOCK_PROCESS_CPUTIME_ID
+#undef CLOCK_THREAD_CPUTIME_ID
+#undef CLOCK_REALTIME_COARSE
+#endif
+#if defined(HAVE_CLOCK_GETTIME) && !defined(CLOCK_REALTIME)
 #define CLOCK_REALTIME  0
 #define CLOCK_MONOTONIC 1
+#endif
 
 #undef utime
 #undef lseek
diff --git a/win32/win32.c b/win32/win32.c
index e1741c0522..89d221550a 100644
--- a/win32/win32.c
+++ b/win32/win32.c
@@ -4806,6 +4806,7 @@ gettimeofday(struct timeval *tv, struct timezone *tz)
     return 0;
 }
 
+#if !defined(__MINGW32__) || !defined(HAVE_CLOCK_GETTIME)
 /* License: Ruby's */
 int
 clock_gettime(clockid_t clock_id, struct timespec *sp)
@@ -4845,7 +4846,9 @@ clock_gettime(clockid_t clock_id, struct timespec *sp)
         return -1;
     }
 }
+#endif
 
+#if !defined(__MINGW32__) || !defined(HAVE_CLOCK_GETRES)
 /* License: Ruby's */
 int
 clock_getres(clockid_t clock_id, struct timespec *sp)
@@ -4873,6 +4876,7 @@ clock_getres(clockid_t clock_id, struct timespec *sp)
         return -1;
     }
 }
+#endif
 
 /* License: Ruby's */
 static char *