diff --git a/CHANGES.md b/CHANGES.md
index d3e9897219d2..b6b66b3e545e 100644
--- a/CHANGES.md
+++ b/CHANGES.md
@@ -4,6 +4,7 @@ Change Log
 ### 1.51 - 2018-11-01
 
 ##### Additions :tada:
+* Shrink minified and gzipped Cesium.js by 27 KB (~3.7%) by delay loading seldom-used third-party dependencies. [#7140](https://github.com/AnalyticalGraphicsInc/cesium/pull/7140)
 * Added WMS-T (time) support in WebMapServiceImageryProvider [#2581](https://github.com/AnalyticalGraphicsInc/cesium/issues/2581)
 * Added `cutoutRectangle` to `ImageryLayer`, which allows cutting out rectangular areas in imagery layers to reveal underlying imagery. [#7056](https://github.com/AnalyticalGraphicsInc/cesium/pull/7056)
 
diff --git a/Source/Core/GoogleEarthEnterpriseMetadata.js b/Source/Core/GoogleEarthEnterpriseMetadata.js
index 32fc531a5387..ef5f4859a817 100644
--- a/Source/Core/GoogleEarthEnterpriseMetadata.js
+++ b/Source/Core/GoogleEarthEnterpriseMetadata.js
@@ -1,6 +1,7 @@
 define([
-        '../ThirdParty/google-earth-dbroot-parser',
+        '../ThirdParty/protobuf-minimal',
         '../ThirdParty/when',
+        './buildModuleUrl',
         './Check',
         './Credit',
         './defaultValue',
@@ -8,14 +9,16 @@ define([
         './defineProperties',
         './GoogleEarthEnterpriseTileInformation',
         './isBitSet',
+        './loadAndExecuteScript',
         './Math',
         './Request',
         './Resource',
         './RuntimeError',
         './TaskProcessor'
     ], function(
-        dbrootParser,
+        protobufMinimal,
         when,
+        buildModuleUrl,
         Check,
         Credit,
         defaultValue,
@@ -23,6 +26,7 @@ define([
         defineProperties,
         GoogleEarthEnterpriseTileInformation,
         isBitSet,
+        loadAndExecuteScript,
         CesiumMath,
         Request,
         Resource,
@@ -488,6 +492,8 @@ define([
         });
     }
 
+    var dbrootParser;
+    var dbrootParserPromise;
     function requestDbRoot(that) {
         var resource = that._resource.getDerivedResource({
             url: 'dbRoot.v5',
@@ -496,8 +502,23 @@ define([
             }
         });
 
-        return resource.fetchArrayBuffer()
-            .then(function(buf) {
+        if (!defined(dbrootParserPromise)) {
+            var url = buildModuleUrl('ThirdParty/google-earth-dbroot-parser.js');
+            var oldValue = window.cesiumGoogleEarthDbRootParser;
+            dbrootParserPromise = loadAndExecuteScript(url)
+                .then(function() {
+                    dbrootParser = window.cesiumGoogleEarthDbRootParser(protobufMinimal);
+                    if (defined(oldValue)) {
+                        window.cesiumGoogleEarthDbRootParser = oldValue;
+                    } else {
+                        delete window.cesiumGoogleEarthDbRootParser;
+                    }
+                });
+        }
+
+        return dbrootParserPromise.then(function() {
+            return resource.fetchArrayBuffer();
+            }).then(function(buf) {
                 var encryptedDbRootProto = dbrootParser.EncryptedDbRootProto.decode(new Uint8Array(buf));
 
                 var byteArray = encryptedDbRootProto.encryptionData;
diff --git a/Source/Core/Resource.js b/Source/Core/Resource.js
index 67301d5fb446..44605eb83007 100644
--- a/Source/Core/Resource.js
+++ b/Source/Core/Resource.js
@@ -10,7 +10,6 @@ define([
         './defineProperties',
         './deprecationWarning',
         './DeveloperError',
-        './FeatureDetection',
         './freezeObject',
         './getAbsoluteUri',
         './getBaseUri',
@@ -18,6 +17,7 @@ define([
         './isBlobUri',
         './isCrossOriginUrl',
         './isDataUri',
+        './loadAndExecuteScript',
         './objectToQuery',
         './queryToObject',
         './Request',
@@ -38,7 +38,6 @@ define([
         defineProperties,
         deprecationWarning,
         DeveloperError,
-        FeatureDetection,
         freezeObject,
         getAbsoluteUri,
         getBaseUri,
@@ -46,6 +45,7 @@ define([
         isBlobUri,
         isCrossOriginUrl,
         isDataUri,
+        loadAndExecuteScript,
         objectToQuery,
         queryToObject,
         Request,
@@ -1934,20 +1934,7 @@ define([
     };
 
     Resource._Implementations.loadAndExecuteScript = function(url, functionName, deferred) {
-        var script = document.createElement('script');
-        script.async = true;
-        script.src = url;
-
-        var head = document.getElementsByTagName('head')[0];
-        script.onload = function() {
-            script.onload = undefined;
-            head.removeChild(script);
-        };
-        script.onerror = function(e) {
-            deferred.reject(e);
-        };
-
-        head.appendChild(script);
+        return loadAndExecuteScript(url, functionName).otherwise(deferred.reject);
     };
 
     /**
diff --git a/Source/Core/loadAndExecuteScript.js b/Source/Core/loadAndExecuteScript.js
new file mode 100644
index 000000000000..877608ad291e
--- /dev/null
+++ b/Source/Core/loadAndExecuteScript.js
@@ -0,0 +1,32 @@
+define([
+    '../ThirdParty/when'
+], function(
+    when) {
+        'use strict';
+
+    /**
+     * @private
+     */
+    function loadAndExecuteScript(url) {
+        var deferred = when.defer();
+        var script = document.createElement('script');
+        script.async = true;
+        script.src = url;
+
+        var head = document.getElementsByTagName('head')[0];
+        script.onload = function() {
+            script.onload = undefined;
+            head.removeChild(script);
+            deferred.resolve();
+        };
+        script.onerror = function(e) {
+            deferred.reject(e);
+        };
+
+        head.appendChild(script);
+
+        return deferred.promise;
+    }
+
+    return loadAndExecuteScript;
+});
diff --git a/Source/ThirdParty/google-earth-dbroot-parser.js b/Source/ThirdParty/google-earth-dbroot-parser.js
index ef369c84aaea..561fc4aa9642 100644
--- a/Source/ThirdParty/google-earth-dbroot-parser.js
+++ b/Source/ThirdParty/google-earth-dbroot-parser.js
@@ -1,6 +1,4 @@
-define([
-    './protobuf-minimal'
-], function(
+window.cesiumGoogleEarthDbRootParser = function(
     $protobuf) {
     /* jshint curly: false, sub: true, newcap: false, shadow: true, unused: false*/
     'use strict';
@@ -8147,4 +8145,4 @@ define([
     // End generated code
 
     return $root.keyhole.dbroot;
-});
+};
diff --git a/gulpfile.js b/gulpfile.js
index 296ce6f724ed..dda17ece6d1e 100644
--- a/gulpfile.js
+++ b/gulpfile.js
@@ -61,6 +61,7 @@ var sourceFiles = ['Source/**/*.js',
                    '!Source/*.js',
                    '!Source/Workers/**',
                    '!Source/ThirdParty/Workers/**',
+                   '!Source/ThirdParty/google-earth-dbroot-parser.js',
                    '!Source/ThirdParty/pako_inflate.js',
                    '!Source/ThirdParty/crunch.js',
                    'Source/Workers/createTaskProcessorWorker.js'];
@@ -891,6 +892,14 @@ function minifyCSS(outputDirectory) {
     });
 }
 
+var gulpUglify = require('gulp-uglify');
+
+function minifyModules(outputDirectory) {
+    return streamToPromise(gulp.src('Source/ThirdParty/google-earth-dbroot-parser.js')
+        .pipe(gulpUglify())
+        .pipe(gulp.dest(outputDirectory + '/ThirdParty/')));
+}
+
 function combineJavaScript(options) {
     var optimizer = options.optimizer;
     var outputDirectory = options.outputDirectory;
@@ -901,7 +910,8 @@ function combineJavaScript(options) {
 
     var promise = Promise.join(
         combineCesium(!removePragmas, optimizer, combineOutput),
-        combineWorkers(!removePragmas, optimizer, combineOutput)
+        combineWorkers(!removePragmas, optimizer, combineOutput),
+        minifyModules(outputDirectory)
     );
 
     return promise.then(function() {
@@ -1264,7 +1274,7 @@ function buildCesiumViewer() {
 
             gulp.src(['Build/Cesium/Assets/**',
                       'Build/Cesium/Workers/**',
-                      'Build/Cesium/ThirdParty/Workers/**',
+                      'Build/Cesium/ThirdParty/**',
                       'Build/Cesium/Widgets/**',
                       '!Build/Cesium/Widgets/**/*.css'],
                 {
diff --git a/package.json b/package.json
index 85886fc29248..6235b74719f8 100644
--- a/package.json
+++ b/package.json
@@ -50,6 +50,7 @@
     "gulp-rename": "^1.2.2",
     "gulp-replace": "^0.6.1",
     "gulp-tap": "^1.0.1",
+    "gulp-uglify": "^3.0.0",
     "gulp-zip": "^4.0.0",
     "jasmine-core": "^3.1.0",
     "jsdoc": "^3.4.3",