diff --git a/app/controllers/invites_controller.rb b/app/controllers/invites_controller.rb
index 1a7f87b7aac..923e822ce0d 100644
--- a/app/controllers/invites_controller.rb
+++ b/app/controllers/invites_controller.rb
@@ -6,6 +6,7 @@ class InvitesController < ApplicationController
 
   before_filter :ensure_logged_in, only: [:destroy, :create, :create_invite_link, :resend_invite, :check_csv_chunk, :upload_csv_chunk]
   before_filter :ensure_new_registrations_allowed, only: [:show, :redeem_disposable_invite]
+  before_filter :ensure_not_logged_in, only: [:show, :redeem_disposable_invite]
 
   def show
     invite = Invite.find_by(invite_key: params[:id])
@@ -195,4 +196,12 @@ class InvitesController < ApplicationController
       false
     end
   end
+
+  def ensure_not_logged_in
+    if current_user
+      flash[:error] = I18n.t("login.already_logged_in", current_user: current_user.username)
+      render layout: 'no_ember'
+      false
+    end
+  end
 end
diff --git a/app/views/invites/redeem_disposable_invite.html.erb b/app/views/invites/redeem_disposable_invite.html.erb
new file mode 100644
index 00000000000..cc4b0acc1e7
--- /dev/null
+++ b/app/views/invites/redeem_disposable_invite.html.erb
@@ -0,0 +1,7 @@
+<div id='simple-container'>
+  <%if flash[:error]%>
+    <div class='alert alert-error'>
+      <%=flash[:error]%>
+    </div>
+  <%end%>
+</div>
diff --git a/config/locales/server.en.yml b/config/locales/server.en.yml
index f3b3e13919b..f81cc685574 100644
--- a/config/locales/server.en.yml
+++ b/config/locales/server.en.yml
@@ -1386,6 +1386,7 @@ en:
     reserved_username: "That username is not allowed."
     missing_user_field: "You have not completed all the user fields"
     close_window: "Authentication is complete. Close this window to continue."
+    already_logged_in: "Oops, looks like you are attempting to accept an invitation for another user. If you are not %{current_user}, please log out and try again?"
 
   user:
     no_accounts_associated: "No accounts associated"
diff --git a/spec/controllers/invites_controller_spec.rb b/spec/controllers/invites_controller_spec.rb
index ca0d4823eb8..745c781f9cb 100644
--- a/spec/controllers/invites_controller_spec.rb
+++ b/spec/controllers/invites_controller_spec.rb
@@ -218,6 +218,16 @@ describe InvitesController do
       end
     end
 
+    context 'user is already logged in' do
+      let!(:user) { log_in }
+      let(:topic) { Fabricate(:topic) }
+      let(:invite) { topic.invite_by_email(topic.user, "iceking@adventuretime.ooo") }
+
+      it "doesn't redeem the invite" do
+        Invite.any_instance.stubs(:redeem).never
+        get :show, id: invite.invite_key
+      end
+    end
   end
 
   context '.create_disposable_invite' do