diff --git a/types/ace-diff/ace-diff-tests.ts b/types/ace-diff/ace-diff-tests.ts
new file mode 100644
index 0000000000..52e64589a3
--- /dev/null
+++ b/types/ace-diff/ace-diff-tests.ts
@@ -0,0 +1,22 @@
+import AceDiff = require('ace-diff');
+
+new AceDiff(); // $ExpectError
+
+const aceDiffConstructorOpts = {
+    element: '.acediff',
+    left: { content: 'left content' },
+    right: { content: 'right content' },
+};
+new AceDiff(aceDiffConstructorOpts); // $ExpectType AceDiff
+
+const differ = new AceDiff(aceDiffConstructorOpts);
+
+differ.getEditors(); // $ExpectType { left: any; right: any; }
+differ.setOptions(); // $ExpectError
+const aceDiffOpts = {
+    diffGranularity: 'broad' as 'broad', // workaround: cast to avoid https://github.com/Microsoft/TypeScript/issues/11465#issuecomment-252453037
+};
+differ.setOptions(aceDiffOpts); // $ExpectType void
+differ.getNumDiffs(); // $ExpectType number
+differ.diff(); // $ExpectType void
+differ.destroy(); // $ExpectType void
diff --git a/types/ace-diff/index.d.ts b/types/ace-diff/index.d.ts
new file mode 100644
index 0000000000..b59b3d25e2
--- /dev/null
+++ b/types/ace-diff/index.d.ts
@@ -0,0 +1,52 @@
+// Type definitions for ace-diff 2.1
+// Project: https://ace-diff.github.io/ace-diff/
+// Definitions by: Mike Dodge <https://github.com/innovation-team>
+// Definitions: https://github.com/DefinitelyTyped/DefinitelyTyped
+
+export as namespace AceDiff;
+
+export = AceDiff;
+
+declare class AceDiff {
+    constructor(opts: AceDiff.AceDiffConstructorOpts);
+    getEditors(): {
+        left: any;
+        right: any;
+    };
+    setOptions(options: AceDiff.AceDiffOpts): void;
+    getNumDiffs(): number;
+    diff(): void;
+    destroy(): void;
+}
+declare namespace AceDiff {
+    interface AceDiffLROpts {
+        content?: string | null;
+        mode?: string;
+        theme?: string;
+        editable?: boolean;
+        copyLinkEnabled?: boolean;
+    }
+
+    interface AceDiffConstructorOpts extends AceDiffOpts {
+        element: string | HTMLElement;
+        left: AceDiffLROpts;
+        right: AceDiffLROpts;
+    }
+
+    interface AceDiffOpts {
+        mode?: string;
+        theme?: string;
+        diffGranularity?: 'specific' | 'broad';
+        showDiffs?: boolean;
+        showConnectors?: boolean;
+        maxDiffs?: number;
+        left?: AceDiffLROpts;
+        right?: AceDiffLROpts;
+        classes?: {
+            diff: string;
+            connector: string;
+            newCodeConnectorLinkContent: string;
+            deletedCodeConnectorLinkContent: string;
+        };
+    }
+}
diff --git a/types/ace-diff/tsconfig.json b/types/ace-diff/tsconfig.json
new file mode 100644
index 0000000000..00fb70bbcd
--- /dev/null
+++ b/types/ace-diff/tsconfig.json
@@ -0,0 +1,24 @@
+{
+    "compilerOptions": {
+        "module": "commonjs",
+        "lib": [
+            "es6",
+            "dom"
+        ],
+        "noImplicitAny": true,
+        "noImplicitThis": true,
+        "strictNullChecks": true,
+        "strictFunctionTypes": true,
+        "baseUrl": "../",
+        "typeRoots": [
+            "../"
+        ],
+        "types": [],
+        "noEmit": true,
+        "forceConsistentCasingInFileNames": true
+    },
+    "files": [
+        "index.d.ts",
+        "ace-diff-tests.ts"
+    ]
+}
diff --git a/types/ace-diff/tslint.json b/types/ace-diff/tslint.json
new file mode 100644
index 0000000000..3db14f85ea
--- /dev/null
+++ b/types/ace-diff/tslint.json
@@ -0,0 +1 @@
+{ "extends": "dtslint/dt.json" }