diff --git a/tools/v8_gypfiles/v8.gyp b/tools/v8_gypfiles/v8.gyp
index 9acad07d966a35..88c1297b9a09ec 100644
--- a/tools/v8_gypfiles/v8.gyp
+++ b/tools/v8_gypfiles/v8.gyp
@@ -41,6 +41,19 @@
         'AdditionalOptions': ['/utf-8']
       }
     },
+    'conditions': [
+      ['OS=="mac"', {
+        # Hide symbols that are not explicitly exported with V8_EXPORT.
+        # TODO(joyeecheung): enable it on other platforms. Currently gcc times out
+        # or run out of memory with -fvisibility=hidden on some machines in the CI.
+        'xcode_settings': {
+          'GCC_SYMBOLS_PRIVATE_EXTERN': 'YES',  # -fvisibility=hidden
+        },
+        'defines': [
+          'BUILDING_V8_SHARED',  # Make V8_EXPORT visible.
+        ],
+      }],
+    ],
   },
   'targets': [
     {