diff --git a/third_party/zlib/zlib.gyp b/third_party/zlib/zlib.gyp
index b6a6bc91..df26cc23 100644
--- a/third_party/zlib/zlib.gyp
+++ b/third_party/zlib/zlib.gyp
@@ -13,18 +13,28 @@
 # limitations under the License.
 
 {
-  'variables': {
-    'conditions': [
-      # Use the system zlib by default where available, as it is on most
-      # platforms. Windows does not have a system zlib, so use “embedded” which
-      # directs the build to use the source code in the zlib subdirectory.
-      ['OS!="win"', {
-        'zlib_source%': 'system',
-      }, {
-        'zlib_source%': 'embedded',
-      }],
-    ],
-  },
+  'includes': [
+    '../../build/crashpad_dependencies.gypi',
+  ],
+  'conditions': [
+    ['1==1', {  # Defer processing until crashpad_dependencies is set
+      'variables': {
+        'conditions': [
+          ['crashpad_dependencies=="external"', {
+            'zlib_source%': 'external',
+          }, 'OS!="win"', {
+            # Use the system zlib by default where available, as it is on most
+            # platforms. Windows does not have a system zlib, so use “embedded”
+            # which directs the build to use the source code in the zlib
+            # subdirectory.
+            'zlib_source%': 'system',
+          }, {
+            'zlib_source%': 'embedded',
+          }],
+        ],
+      },
+    }],
+  ],
   'targets': [
     {
       'target_name': 'zlib',
@@ -141,6 +151,17 @@
             }],
           ],
         }],
+        ['zlib_source=="external"', {
+          'type': 'none',
+          'direct_dependent_settings': {
+            'defines': [
+              'CRASHPAD_ZLIB_SOURCE_EXTERNAL',
+            ],
+          },
+          'dependencies': [
+            '../../../../zlib/zlib.gyp:zlib',
+          ],
+        }],
       ],
     },
   ],
diff --git a/third_party/zlib/zlib_crashpad.h b/third_party/zlib/zlib_crashpad.h
index d3a23861..fd497a85 100644
--- a/third_party/zlib/zlib_crashpad.h
+++ b/third_party/zlib/zlib_crashpad.h
@@ -19,9 +19,8 @@
 // available at any other location in the source tree. It will #include the
 // proper <zlib.h> depending on how the build has been configured.
 
-#if defined(CRASHPAD_ZLIB_SOURCE_EXTERNAL)
-#include "third_party/zlib/zlib.h"
-#elif defined(CRASHPAD_ZLIB_SOURCE_SYSTEM)
+#if defined(CRASHPAD_ZLIB_SOURCE_SYSTEM) || \
+    defined(CRASHPAD_ZLIB_SOURCE_EXTERNAL)
 #include <zlib.h>
 #elif defined(CRASHPAD_ZLIB_SOURCE_EMBEDDED)
 #include "third_party/zlib/zlib/zlib.h"