diff --git a/package.json b/package.json
index 17d9b16646680f..eb17c3d2b7eb1f 100644
--- a/package.json
+++ b/package.json
@@ -63,7 +63,7 @@
     "babel-runtime": "^6.26.0",
     "brcast": "^3.0.1",
     "classnames": "^2.2.5",
-    "deepmerge": "^1.5.2",
+    "deepmerge": "^2.0.0",
     "dom-helpers": "^3.2.1",
     "hoist-non-react-statics": "^1.2.0",
     "jss": "^8.1.0",
@@ -95,7 +95,7 @@
     "babel-loader": "^7.1.2",
     "babel-plugin-flow-react-proptypes": "6.1.0",
     "babel-plugin-istanbul": "^4.1.5",
-    "babel-plugin-preval": "^1.5.0",
+    "babel-plugin-preval": "^1.5.1",
     "babel-plugin-react-remove-properties": "^0.2.5",
     "babel-plugin-transform-dev-warning": "^0.1.0",
     "babel-plugin-transform-flow-strip-types": "^6.22.0",
@@ -143,7 +143,7 @@
     "karma-mocha-reporter": "^2.2.4",
     "karma-phantomjs-launcher": "^1.0.4",
     "karma-sourcemap-loader": "^0.3.7",
-    "karma-webpack": "^2.0.4",
+    "karma-webpack": "^2.0.5",
     "marked": "^0.3.6",
     "mocha": "^4.0.1",
     "next": "^3.2.2",
diff --git a/src/styles/createMuiTheme.js b/src/styles/createMuiTheme.js
index 5debe51404af3b..3bb16d597de68c 100644
--- a/src/styles/createMuiTheme.js
+++ b/src/styles/createMuiTheme.js
@@ -36,9 +36,6 @@ function createMuiTheme(options: Object = {}) {
         zIndex,
       },
       other,
-      {
-        clone: true, // We don't want to mutate the input
-      },
     ),
   };
 }
diff --git a/src/styles/createPalette.js b/src/styles/createPalette.js
index cf15f93ec6e15b..b7018c75e2519e 100644
--- a/src/styles/createPalette.js
+++ b/src/styles/createPalette.js
@@ -96,6 +96,9 @@ export default function createPalette(palette: Object) {
       getContrastText,
     },
     other,
+    {
+      clone: false, // No need to clone deep
+    },
   );
 
   // Dev warnings
diff --git a/src/styles/createTypography.js b/src/styles/createTypography.js
index d4fd4e1a3f9567..e52853e143ff6d 100644
--- a/src/styles/createTypography.js
+++ b/src/styles/createTypography.js
@@ -110,5 +110,8 @@ export default function createTypography(palette: Object, typography: Object | F
       },
     },
     other,
+    {
+      clone: false, // No need to clone deep
+    },
   );
 }
diff --git a/src/styles/getStylesCreator.js b/src/styles/getStylesCreator.js
index 81639ee5b9044b..9a0087c47d175b 100644
--- a/src/styles/getStylesCreator.js
+++ b/src/styles/getStylesCreator.js
@@ -16,9 +16,7 @@ function getStylesCreator(stylesOrCreator: Object | (Object => Object)) {
 
     Object.keys(overrides).forEach(key => {
       warning(stylesWithOverrides[key], 'You are trying to overrides a style that do not exist.');
-      stylesWithOverrides[key] = deepmerge(stylesWithOverrides[key], overrides[key], {
-        clone: true, // We don't want to mutate the input
-      });
+      stylesWithOverrides[key] = deepmerge(stylesWithOverrides[key], overrides[key]);
     });
 
     return stylesWithOverrides;
diff --git a/yarn.lock b/yarn.lock
index 62d10fe8a0ed2a..e698250340be6c 100644
--- a/yarn.lock
+++ b/yarn.lock
@@ -785,9 +785,9 @@ babel-plugin-module-resolver@2.6.2:
     glob "^7.1.1"
     resolve "^1.3.2"
 
-babel-plugin-preval@^1.5.0:
-  version "1.5.0"
-  resolved "https://registry.yarnpkg.com/babel-plugin-preval/-/babel-plugin-preval-1.5.0.tgz#be4e3353ce6ec4fd0c6b199701193306033bf54b"
+babel-plugin-preval@^1.5.1:
+  version "1.5.1"
+  resolved "https://registry.yarnpkg.com/babel-plugin-preval/-/babel-plugin-preval-1.5.1.tgz#e4f4466a71561a4aae3c79c0b44627e68a3ab9a6"
   dependencies:
     babel-core "^6.26.0"
     babel-macros "^1.0.0"
@@ -2578,9 +2578,9 @@ deep-is@~0.1.3:
   version "0.1.3"
   resolved "https://registry.yarnpkg.com/deep-is/-/deep-is-0.1.3.tgz#b369d6fb5dbc13eecf524f91b070feedc357cf34"
 
-deepmerge@^1.5.2:
-  version "1.5.2"
-  resolved "https://registry.yarnpkg.com/deepmerge/-/deepmerge-1.5.2.tgz#10499d868844cdad4fee0842df8c7f6f0c95a753"
+deepmerge@^2.0.0:
+  version "2.0.0"
+  resolved "https://registry.yarnpkg.com/deepmerge/-/deepmerge-2.0.0.tgz#35f7ee08e8bde1173b3a529f732dcda67ce82e29"
 
 default-require-extensions@^1.0.0:
   version "1.0.0"
@@ -5104,9 +5104,9 @@ karma-sourcemap-loader@^0.3.7:
   dependencies:
     graceful-fs "^4.1.2"
 
-karma-webpack@^2.0.4:
-  version "2.0.4"
-  resolved "https://registry.yarnpkg.com/karma-webpack/-/karma-webpack-2.0.4.tgz#3e2d4f48ba94a878e1c66bb8e1ae6128987a175b"
+karma-webpack@^2.0.5:
+  version "2.0.5"
+  resolved "https://registry.yarnpkg.com/karma-webpack/-/karma-webpack-2.0.5.tgz#4f56887e32cf4f9583391c2388415de06af06efd"
   dependencies:
     async "~0.9.0"
     loader-utils "^0.2.5"