diff --git a/lib/integrations/slack/slack_message_helper.rb b/lib/integrations/slack/slack_message_helper.rb
index 52ec4caad..0ee328fb3 100644
--- a/lib/integrations/slack/slack_message_helper.rb
+++ b/lib/integrations/slack/slack_message_helper.rb
@@ -70,7 +70,9 @@ module Integrations::Slack::SlackMessageHelper
     case attachment[:filetype]
     when 'png', 'jpeg', 'gif', 'bmp', 'tiff', 'jpg'
       :image
-    when 'pdf'
+    when 'mp4', 'avi', 'mov', 'wmv', 'flv', 'webm'
+      :video
+    else
       :file
     end
   end
diff --git a/spec/lib/integrations/slack/incoming_message_builder_spec.rb b/spec/lib/integrations/slack/incoming_message_builder_spec.rb
index 608324e8f..2ce206489 100644
--- a/spec/lib/integrations/slack/incoming_message_builder_spec.rb
+++ b/spec/lib/integrations/slack/incoming_message_builder_spec.rb
@@ -157,6 +157,19 @@ describe Integrations::Slack::IncomingMessageBuilder do
 
         expect(conversation.messages.count).to eql(messages_count)
       end
+
+      it 'handles different file types correctly' do
+        expect(hook).not_to be_nil
+        video_attachment_params = message_with_attachments.deep_dup
+        video_attachment_params[:event][:files][0][:filetype] = 'mp4'
+        video_attachment_params[:event][:files][0][:mimetype] = 'video/mp4'
+
+        builder = described_class.new(video_attachment_params)
+        allow(builder).to receive(:sender).and_return(nil)
+
+        expect { builder.perform }.not_to raise_error
+        expect(conversation.messages.last.attachments).to be_any
+      end
     end
 
     context 'when link shared' do