diff --git a/ghost/core/core/server/services/slack.js b/ghost/core/core/server/services/slack.js
index b2027ea85f..be9916e4bc 100644
--- a/ghost/core/core/server/services/slack.js
+++ b/ghost/core/core/server/services/slack.js
@@ -63,7 +63,24 @@ function ping(post) {
         if (post.custom_excerpt) {
             description = post.custom_excerpt;
         } else if (post.html) {
-            description = `${post.html.replace(/<[^>]+>/g, '').split('.').slice(0, 3).join('.')}.`;
+            const membersContentIdx = post.html.indexOf('<!--members-only-->');
+            const substringEnd = membersContentIdx > -1 ? membersContentIdx : post.html.length;
+
+            description = `${
+                post.html
+                    // Remove members-only content
+                    .substring(0, substringEnd)
+                    // Strip out HTML
+                    .replace(/<[^>]+>/g, '')
+                    // Split into sentences
+                    .split('.')
+                    // Remove empty strings
+                    .filter(sentence => sentence.trim() !== '')
+                    // Get the first three sentences
+                    .slice(0, 3)
+                    // Join 'em back together
+                    .join('.')
+            }.`;
         } else {
             description = null;
         }
@@ -160,7 +177,10 @@ function slackListener(model, options) {
         return;
     }
 
-    ping(model.toJSON());
+    ping({
+        ...model.toJSON(),
+        authors: model.related('authors').toJSON()
+    });
 }
 
 function slackTestPing() {
diff --git a/ghost/core/test/unit/server/services/slack.test.js b/ghost/core/test/unit/server/services/slack.test.js
index be3a019254..7b9b45f5ee 100644
--- a/ghost/core/test/unit/server/services/slack.test.js
+++ b/ghost/core/test/unit/server/services/slack.test.js
@@ -38,10 +38,22 @@ describe('Slack', function () {
 
     it('listener() calls ping() with toJSONified model', function () {
         const testPost = _.clone(testUtils.DataGenerator.Content.posts[2]);
+        const testAuthor = _.clone(testUtils.DataGenerator.Content.users[0]);
 
         const testModel = {
             toJSON: function () {
                 return testPost;
+            },
+            related: function (relation) {
+                return {
+                    toJSON: function () {
+                        if (relation === 'authors') {
+                            return [testAuthor];
+                        }
+
+                        return [];
+                    }
+                };
             }
         };
 
@@ -52,7 +64,10 @@ describe('Slack', function () {
         listener(testModel);
 
         pingStub.calledOnce.should.be.true();
-        pingStub.calledWith(testPost).should.be.true();
+        pingStub.calledWith({
+            ...testPost,
+            authors: [testAuthor]
+        }).should.be.true();
 
         // Reset slack ping method
         resetSlack();
@@ -121,7 +136,10 @@ describe('Slack', function () {
             let requestUrl;
             let requestData;
 
-            const post = testUtils.DataGenerator.forKnex.createPost({slug: 'webhook-test'});
+            const post = testUtils.DataGenerator.forKnex.createPost({
+                slug: 'webhook-test',
+                html: `<p>Hello World!</p><p>This is a test post.</p><!--members-only--><p>This is members only content.</p>`
+            });
             urlService.getUrlByResourceId.withArgs(post.id, {absolute: true}).returns('http://myblog.com/' + post.slug + '/');
 
             settingsCacheStub.withArgs('slack_url').returns(slackURL);
@@ -140,7 +158,7 @@ describe('Slack', function () {
             requestUrl.should.equal(slackURL);
             requestData.attachments[0].title.should.equal(post.title);
             requestData.attachments[0].title_link.should.equal('http://myblog.com/webhook-test/');
-            requestData.attachments[0].fields[0].value.should.equal('## markdown.');
+            requestData.attachments[0].fields[0].value.should.equal('Hello World!This is a test post.');
             requestData.attachments[0].should.not.have.property('author_name');
             requestData.icon_url.should.equal('http://myblog.com/favicon.ico');