diff --git a/BUILD.gn b/BUILD.gn
index f22a418..a21c0da 100644
--- a/BUILD.gn
+++ b/BUILD.gn
@@ -18,7 +18,6 @@
     "PNG_PREFIX",
     "PNG_USE_READ_MACROS",
     "V8_DEPRECATION_WARNINGS",
-    "_CRT_SECURE_NO_WARNINGS",
   ]
 
   if (pdf_use_skia) {
diff --git a/core/fxcrt/include/fx_system.h b/core/fxcrt/include/fx_system.h
index 22fdef2..4900634 100644
--- a/core/fxcrt/include/fx_system.h
+++ b/core/fxcrt/include/fx_system.h
@@ -54,7 +54,6 @@
 #endif
 
 #if _FXM_PLATFORM_ == _FXM_PLATFORM_WINDOWS_
-#define _CRT_SECURE_NO_WARNINGS
 #include <windows.h>
 #include <sal.h>
 #endif
diff --git a/pdfium.gyp b/pdfium.gyp
index e61237f..06f960b 100644
--- a/pdfium.gyp
+++ b/pdfium.gyp
@@ -57,7 +57,6 @@
       'PNG_PREFIX',
       'PNG_USE_READ_MACROS',
       'V8_DEPRECATION_WARNINGS',
-      '_CRT_SECURE_NO_WARNINGS',
     ],
     'include_dirs': [
       # This is implicit in GN.
@@ -94,7 +93,7 @@
       }],
     ],
     'msvs_disabled_warnings': [
-      4005, 4018, 4146, 4333, 4345, 4267,
+      4018, 4146, 4333, 4345, 4267,
     ],
     'variables': {
       'clang_warning_flags': [