diff --git a/README.md b/README.md
index 5e691924..5b044146 100644
--- a/README.md
+++ b/README.md
@@ -89,7 +89,8 @@ Add this Action as a [step][job-step] to your project's GitHub Action Workflow f
   with:
     # Slack channel id, channel name, or user id to post message.
     # See also: https://api.slack.com/methods/chat.postMessage#channels
-    channel-id: 'CHANNEL_ID'
+    # You can pass in multiple channels to post to by providing a comma-delimited list of channel IDs.
+    channel-id: 'CHANNEL_ID,ANOTHER_CHANNEL_ID'
     # For posting a simple plain text message
     slack-message: "GitHub build result: ${{ job.status }}\n${{ github.event.pull_request.html_url || github.event.head_commit.url }}"
   env:
diff --git a/src/slack-send.js b/src/slack-send.js
index 98dbf561..5bb66438 100644
--- a/src/slack-send.js
+++ b/src/slack-send.js
@@ -60,25 +60,27 @@ module.exports = async function slackSend(core) {
 
     if (typeof botToken !== 'undefined' && botToken.length > 0) {
       const message = core.getInput('slack-message') || '';
-      const channelId = core.getInput('channel-id') || '';
+      const channelIds = core.getInput('channel-id') || '';
       const web = new WebClient(botToken);
 
-      if (channelId.length <= 0) {
+      if (channelIds.length <= 0) {
         console.log('Channel ID is required to run this action. An empty one has been provided');
         throw new Error('Channel ID is required to run this action. An empty one has been provided');
       }
 
       if (message.length > 0 || payload) {
         const ts = core.getInput('update-ts');
-        if (ts) {
+        await Promise.all(channelIds.split(',').map(async (channelId) => {
+          if (ts) {
           // update message
-          webResponse = await web.chat.update({ ts, channel: channelId, text: message, ...(payload || {}) });
-        } else {
+            webResponse = await web.chat.update({ ts, channel: channelId.trim(), text: message, ...(payload || {}) });
+          } else {
           // post message
-          webResponse = await web.chat.postMessage({ channel: channelId, text: message, ...(payload || {}) });
-        }
+            webResponse = await web.chat.postMessage({ channel: channelId.trim(), text: message, ...(payload || {}) });
+          }
+        }));
       } else {
-        console.log('Missing slack-message or payload! Did not send a message via chat.postMessage with botToken', { channel: channelId, text: message, ...(payload) });
+        console.log('Missing slack-message or payload! Did not send a message via chat.postMessage with botToken', { channel: channelIds, text: message, ...(payload) });
         throw new Error('Missing message content, please input a valid payload or message to send. No Message has been send.');
       }
     }
diff --git a/test/slack-send-test.js b/test/slack-send-test.js
index 98c6b3b9..b6838f56 100644
--- a/test/slack-send-test.js
+++ b/test/slack-send-test.js
@@ -105,6 +105,18 @@ describe('slack-send', () => {
         assert.equal(chatArgs.oliver, 'benji', 'Correct message provided to postMessage');
         assert.equal(chatArgs.actor, 'user123', 'Correct message provided to postMessage');
       });
+
+      it('should send the same message to multiple channels', async () => {
+        fakeCore.getInput.withArgs('slack-message').returns('who let the dogs out?');
+        fakeCore.getInput.withArgs('channel-id').returns('C123456,C987654');
+        await slackSend(fakeCore);
+        const firstChatArgs = ChatStub.postMessage.firstCall.firstArg;
+        const secondChatArgs = ChatStub.postMessage.lastCall.firstArg;
+        assert.oneOf('C123456', [firstChatArgs.channel, secondChatArgs.channel], 'First comma-separated channel provided to postMessage');
+        assert.oneOf('C987654', [firstChatArgs.channel, secondChatArgs.channel], 'Second comma-separated channel provided to postMessage');
+        assert.equal(firstChatArgs.text, 'who let the dogs out?', 'Correct message provided to postMessage with first comma-separated channel');
+        assert.equal(secondChatArgs.text, 'who let the dogs out?', 'Correct message provided to postMessage with second comma-separated channel');
+      });
     });
     describe('sad path', () => {
       it('should set an error if payload cannot be JSON parsed', async () => {