diff --git a/ghost/core/core/server/services/slack.js b/ghost/core/core/server/services/slack.js
index 7653d0c477..b2027ea85f 100644
--- a/ghost/core/core/server/services/slack.js
+++ b/ghost/core/core/server/services/slack.js
@@ -153,7 +153,7 @@ function ping(post) {
     }
 }
 
-function listener(model, options) {
+function slackListener(model, options) {
     // CASE: do not ping slack if we import a database
     // TODO: refactor post.published events to never fire on importing
     if (options && options.importing) {
@@ -163,15 +163,20 @@ function listener(model, options) {
     ping(model.toJSON());
 }
 
-function testPing() {
+function slackTestPing() {
     ping({
         message: 'Heya! This is a test notification from your Ghost blog :smile:. Seems to work fine!'
     });
 }
 
 function listen() {
-    events.on('post.published', listener);
-    events.on('slack.test', testPing);
+    if (!events.hasRegisteredListener('post.published', 'slackListener')) {
+        events.on('post.published', slackListener);
+    }
+
+    if (!events.hasRegisteredListener('slack.test', 'slackTestPing')) {
+        events.on('slack.test', slackTestPing);
+    }
 }
 
 // Public API
diff --git a/ghost/core/test/unit/server/services/slack.test.js b/ghost/core/test/unit/server/services/slack.test.js
index 0a8a537dd8..be3a019254 100644
--- a/ghost/core/test/unit/server/services/slack.test.js
+++ b/ghost/core/test/unit/server/services/slack.test.js
@@ -32,8 +32,8 @@ describe('Slack', function () {
     it('listen() should initialise event correctly', function () {
         slack.listen();
         eventStub.calledTwice.should.be.true();
-        eventStub.firstCall.calledWith('post.published', slack.__get__('listener')).should.be.true();
-        eventStub.secondCall.calledWith('slack.test', slack.__get__('testPing')).should.be.true();
+        eventStub.firstCall.calledWith('post.published', slack.__get__('slackListener')).should.be.true();
+        eventStub.secondCall.calledWith('slack.test', slack.__get__('slackTestPing')).should.be.true();
     });
 
     it('listener() calls ping() with toJSONified model', function () {
@@ -47,7 +47,7 @@ describe('Slack', function () {
 
         const pingStub = sinon.stub();
         const resetSlack = slack.__set__('ping', pingStub);
-        const listener = slack.__get__('listener');
+        const listener = slack.__get__('slackListener');
 
         listener(testModel);
 
@@ -69,7 +69,7 @@ describe('Slack', function () {
 
         const pingStub = sinon.stub();
         const resetSlack = slack.__set__('ping', pingStub);
-        const listener = slack.__get__('listener');
+        const listener = slack.__get__('slackListener');
 
         listener(testModel, {importing: true});
 
@@ -82,7 +82,7 @@ describe('Slack', function () {
     it('testPing() calls ping() with default message', function () {
         const pingStub = sinon.stub();
         const resetSlack = slack.__set__('ping', pingStub);
-        const testPing = slack.__get__('testPing');
+        const testPing = slack.__get__('slackTestPing');
 
         testPing();