diff --git a/app/mailers/task_mailer.rb b/app/mailers/task_mailer.rb
index 9720c64..5b40db5 100644
--- a/app/mailers/task_mailer.rb
+++ b/app/mailers/task_mailer.rb
@@ -40,7 +40,8 @@ class TaskMailer < ActionMailer::Base
       to: task.requestor.notification_emails,
       from: self.class.generate_from(task),
       subject: @email_template.present? ? @email_template.parsed_subject(template_params) : '[%s] %s' % [task.requestor.environment.name, task.target_notification_description],
-      body: @email_template.present? ? @email_template.parsed_body(template_params) : nil
+      body: @email_template.present? ? @email_template.parsed_body(template_params) : nil,
+      content_type: @email_template.present? ? "text/html" : nil
     )
   end
 
diff --git a/test/unit/task_mailer_test.rb b/test/unit/task_mailer_test.rb
index 90ce7dc..d83a0e5 100644
--- a/test/unit/task_mailer_test.rb
+++ b/test/unit/task_mailer_test.rb
@@ -190,6 +190,7 @@ class TaskMailerTest < ActiveSupport::TestCase
     task.send(:send_notification, :cancelled).deliver
     assert !ActionMailer::Base.deliveries.empty?
     mail = ActionMailer::Base.deliveries.last
+    assert_match /text\/html/, mail.content_type
     assert_equal 'template subject - example', mail.subject.to_s
     assert_equal 'template body - example - my name - explanation', mail.body.to_s
   end
--
libgit2 0.21.2