diff --git a/crypto/bio/bio_print.c b/crypto/bio/bio_print.c
index ea77be4046..8b0c3481f0 100644
--- a/crypto/bio/bio_print.c
+++ b/crypto/bio/bio_print.c
@@ -72,7 +72,7 @@ static int msvc_bio_vprintf(BIO *bio, const char *format, va_list args)
 }
 #endif
 
-#ifdef _WIN32
+#ifdef _MSC_VER
 /*
  * This function is for unit test on windows only when built with Visual Studio
  */
diff --git a/include/internal/bio.h b/include/internal/bio.h
index e814a269d6..91a27b2218 100644
--- a/include/internal/bio.h
+++ b/include/internal/bio.h
@@ -107,7 +107,7 @@ int ossl_core_bio_vprintf(OSSL_CORE_BIO *cb, const char *format, va_list args);
 
 int ossl_bio_init_core(OSSL_LIB_CTX *libctx, const OSSL_DISPATCH *fns);
 
-#ifdef _WIN32
+#ifdef _MSC_VER
 int ossl_BIO_snprintf_msvc(char *buf, size_t n, const char *fmt, ...);
 #endif
 
diff --git a/test/bioprinttest.c b/test/bioprinttest.c
index fb7d9d82d6..bbf6dcc056 100644
--- a/test/bioprinttest.c
+++ b/test/bioprinttest.c
@@ -315,7 +315,7 @@ static int test_int(int i)
     return 1;
 }
 
-#ifdef _WIN32
+#ifdef _MSC_VER
 static int test_int_win32(int i)
 {
     int ret;
@@ -460,7 +460,7 @@ static int test_width_precision(int i)
     return 1;
 }
 
-#ifdef _WIN32
+#ifdef _MSC_VER
 static int test_width_precision_win32(int i)
 {
     int ret;
@@ -691,7 +691,7 @@ static int test_zu(int i)
     return 1;
 }
 
-#ifdef _WIN32
+#ifdef _MSC_VER
 static int test_zu_win32(int i)
 {
     int ret;
@@ -734,7 +734,7 @@ static int test_t(int i)
     return 1;
 }
 
-#ifdef _WIN32
+#ifdef _MSC_VER
 static int test_t_win32(int i)
 {
     int ret;
@@ -781,7 +781,7 @@ static int test_j(int i)
     return 1;
 }
 
-#ifdef _WIN32
+#ifdef _MSC_VER
 static int test_j_win32(int i)
 {
     int ret;
@@ -877,7 +877,7 @@ static int test_fp(int i)
     return r;
 }
 
-#ifdef _WIN32
+#ifdef _MSC_VER
 static int test_fp_win32(int i)
 {
     int ret;
@@ -931,7 +931,7 @@ int setup_tests(void)
     ADD_ALL_TESTS(test_t, OSSL_NELEM(t_data));
     ADD_ALL_TESTS(test_j, OSSL_NELEM(jf_data));
 
-#ifdef _WIN32
+#ifdef _MSC_VER
     /*
      * those tests are using _vsnprintf_s()
      */