diff --git a/CHANGELOG.md b/CHANGELOG.md
index a0e0ec79..58c4c7f1 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -2,6 +2,8 @@
 
 ## HEAD (Unreleased)
 
+- feat: comment on GitHub step summary.
+  ([#986](https://github.com/pulumi/actions/pull/986))
 - feat: Add Update Plan Functionality
   ([#994](https://github.com/pulumi/actions/pull/994))
 
diff --git a/README.md b/README.md
index 3e9917d3..01889a58 100644
--- a/README.md
+++ b/README.md
@@ -54,6 +54,9 @@ The action can be configured with the following arguments:
   of the Pulumi action to the PR. Ignored unless `${{ github.event }}` type is
   `pull_request`.
 
+- `comment-on-summary` - (optional) If `true`, then the action will add the
+  results of the Pulumi action to the GitHub step summary.
+
 - `github-token` - (optional) A GitHub token that has access levels to allow the
   Action to comment on a PR. Defaults to `${{ github.token }}`
 
diff --git a/action.yml b/action.yml
index 0f5b995e..b4c7b5e7 100644
--- a/action.yml
+++ b/action.yml
@@ -26,6 +26,10 @@ inputs:
   comment-on-pr-number:
     description: 'Overrides the PR used to comment on'
     required: false
+  comment-on-summary:
+    description: 'If true, a comment on the GitHub step summary will be created'
+    required: false
+    default: 'false'
   github-token:
     description: 'Github Token'
     required: false
diff --git a/src/__tests__/config.test.ts b/src/__tests__/config.test.ts
index c6b1344d..8e821edd 100644
--- a/src/__tests__/config.test.ts
+++ b/src/__tests__/config.test.ts
@@ -8,6 +8,7 @@ const defaultConfig: Record<string, string> = {
   'github-token': 'n/a',
   'pulumi-version': '^3',
   'comment-on-pr': 'false',
+  'comment-on-summary': 'false',
   upsert: 'false',
   remove: 'false',
   refresh: 'false',
@@ -40,6 +41,7 @@ describe('config.ts', () => {
         "command": "up",
         "commentOnPr": false,
         "commentOnPrNumber": undefined,
+        "commentOnSummary": false,
         "configMap": undefined,
         "editCommentOnPr": false,
         "githubToken": "n/a",
diff --git a/src/config.ts b/src/config.ts
index f84e0270..52ca7880 100644
--- a/src/config.ts
+++ b/src/config.ts
@@ -43,6 +43,7 @@ export function makeConfig() {
     githubToken: getInput('github-token'),
     commentOnPr: getBooleanInput('comment-on-pr'),
     commentOnPrNumber: getNumberInput('comment-on-pr-number', {}),
+    commentOnSummary: getBooleanInput('comment-on-summary'),
     upsert: getBooleanInput('upsert'),
     remove: getBooleanInput('remove'),
     refresh: getBooleanInput('refresh'),
diff --git a/src/main.ts b/src/main.ts
index 24f48e59..c3b7031c 100644
--- a/src/main.ts
+++ b/src/main.ts
@@ -124,6 +124,13 @@ const runAction = async (config: Config): Promise<void> => {
     }
   }
 
+  if (config.commentOnSummary) {
+    await core.summary
+      .addHeading(`Pulumi ${config.stackName} results`)
+      .addCodeBlock(output, "diff")
+      .write();
+  }
+
   if (config.remove && config.command === 'destroy') {
     stack.workspace.removeStack(stack.name);
   }