diff --git a/action.yml b/action.yml
index 0077ecd..97cddcf 100644
--- a/action.yml
+++ b/action.yml
@@ -1,3 +1,6 @@
+# Copyright (c) HashiCorp, Inc.
+# SPDX-License-Identifier: MPL-2.0
+
 name: 'HashiCorp - Setup Terraform'
 description: 'Sets up Terraform CLI in your GitHub Actions workflow.'
 author: 'HashiCorp, Inc.'
diff --git a/index.js b/index.js
index 05a049a..aa9fd40 100644
--- a/index.js
+++ b/index.js
@@ -1,3 +1,8 @@
+/**
+ * Copyright (c) HashiCorp, Inc.
+ * SPDX-License-Identifier: MPL-2.0
+ */
+
 const core = require('@actions/core');
 
 const setup = require('./lib/setup-terraform');
diff --git a/lib/setup-terraform.js b/lib/setup-terraform.js
index 1e61d2c..3e726cf 100644
--- a/lib/setup-terraform.js
+++ b/lib/setup-terraform.js
@@ -1,3 +1,8 @@
+/**
+ * Copyright (c) HashiCorp, Inc.
+ * SPDX-License-Identifier: MPL-2.0
+ */
+
 // Node.js core
 const fs = require('fs').promises;
 const os = require('os');
diff --git a/test/setup-terraform.test.js b/test/setup-terraform.test.js
index 367de90..57cda0f 100644
--- a/test/setup-terraform.test.js
+++ b/test/setup-terraform.test.js
@@ -1,3 +1,8 @@
+/**
+ * Copyright (c) HashiCorp, Inc.
+ * SPDX-License-Identifier: MPL-2.0
+ */
+
 // Mock external modules by default
 jest.mock('@actions/core');
 jest.mock('@actions/tool-cache');
diff --git a/wrapper/lib/output-listener.js b/wrapper/lib/output-listener.js
index 248561e..9686dba 100644
--- a/wrapper/lib/output-listener.js
+++ b/wrapper/lib/output-listener.js
@@ -1,3 +1,8 @@
+/**
+ * Copyright (c) HashiCorp, Inc.
+ * SPDX-License-Identifier: MPL-2.0
+ */
+
 /**
  * Acts as a listener for @actions/exec, by capturing STDOUT and STDERR
  * streams, and exposing them via a contents attribute.
diff --git a/wrapper/lib/terraform-bin.js b/wrapper/lib/terraform-bin.js
index 3616d8f..478ff6a 100644
--- a/wrapper/lib/terraform-bin.js
+++ b/wrapper/lib/terraform-bin.js
@@ -1,3 +1,8 @@
+/**
+ * Copyright (c) HashiCorp, Inc.
+ * SPDX-License-Identifier: MPL-2.0
+ */
+
 const os = require('os');
 const path = require('path');
 
diff --git a/wrapper/terraform.js b/wrapper/terraform.js
index b0311af..eddcb35 100755
--- a/wrapper/terraform.js
+++ b/wrapper/terraform.js
@@ -1,4 +1,9 @@
 #!/usr/bin/env node
+/**
+ * Copyright (c) HashiCorp, Inc.
+ * SPDX-License-Identifier: MPL-2.0
+ */
+
 const io = require('@actions/io');
 const core = require('@actions/core');
 const { exec } = require('@actions/exec');
diff --git a/wrapper/test/output-listener.test.js b/wrapper/test/output-listener.test.js
index 6023ab5..229c3cf 100644
--- a/wrapper/test/output-listener.test.js
+++ b/wrapper/test/output-listener.test.js
@@ -1,3 +1,8 @@
+/**
+ * Copyright (c) HashiCorp, Inc.
+ * SPDX-License-Identifier: MPL-2.0
+ */
+
 const OutputListener = require('../lib/output-listener');
 
 describe('output-listener', () => {