diff --git a/types/activestorage/activestorage-tests.ts b/types/activestorage/activestorage-tests.ts
new file mode 100644
index 0000000000..ac9622e2d8
--- /dev/null
+++ b/types/activestorage/activestorage-tests.ts
@@ -0,0 +1,28 @@
+import * as ActiveStorage from 'activestorage';
+
+ActiveStorage.start();
+
+const delegate: ActiveStorage.DirectUploadDelegate = {
+    directUploadWillCreateBlobWithXHR(xhr) {
+        console.log(xhr.status);
+    },
+
+    directUploadWillStoreFileWithXHR(xhr) {
+        console.log(xhr.status);
+    },
+};
+
+const d = new ActiveStorage.DirectUpload(
+    new File([], 'blank.txt'),
+    '/rails/active_storage/direct_uploads',
+    delegate
+);
+
+d.create((error, blob) => {
+    if (error) {
+        console.log(error.message);
+    } else {
+        const { byte_size, checksum, content_type, filename, signed_id } = blob;
+        console.log({ byte_size, checksum, content_type, filename, signed_id });
+    }
+});
diff --git a/types/activestorage/index.d.ts b/types/activestorage/index.d.ts
new file mode 100644
index 0000000000..2d749c84ec
--- /dev/null
+++ b/types/activestorage/index.d.ts
@@ -0,0 +1,33 @@
+// Type definitions for ActiveStorage 5.2
+// Project: https://github.com/rails/rails/tree/master/activestorage/app/javascipt
+// Definitions by: Cameron Bothner <https://github.com/cbothner>
+// Definitions: https://github.com/cbothner/DefinitelyTyped
+// TypeScript Version: 2.1
+
+export as namespace ActiveStorage
+
+export function start(): void;
+
+export class DirectUpload {
+    id: number;
+    file: File;
+    url: string;
+
+    constructor(file: File, url: string, delegate: DirectUploadDelegate)
+
+    create(callback: (error: Error, blob: Blob) => void): void;
+}
+
+export interface DirectUploadDelegate {
+    directUploadWillCreateBlobWithXHR?: (xhr: XMLHttpRequest) => void;
+
+    directUploadWillStoreFileWithXHR?: (xhr: XMLHttpRequest) => void;
+}
+
+export interface Blob {
+    byte_size: number;
+    checksum: string;
+    content_type: string;
+    filename: string;
+    signed_id: string;
+}
diff --git a/types/activestorage/tsconfig.json b/types/activestorage/tsconfig.json
new file mode 100644
index 0000000000..326c2c7401
--- /dev/null
+++ b/types/activestorage/tsconfig.json
@@ -0,0 +1,16 @@
+{
+    "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", "activestorage-tests.ts"]
+}
diff --git a/types/activestorage/tslint.json b/types/activestorage/tslint.json
new file mode 100644
index 0000000000..3db14f85ea
--- /dev/null
+++ b/types/activestorage/tslint.json
@@ -0,0 +1 @@
+{ "extends": "dtslint/dt.json" }