diff --git a/app/views/submitter_mailer/completed_email.html.erb b/app/views/submitter_mailer/completed_email.html.erb
index 70792c86..7269fb39 100644
--- a/app/views/submitter_mailer/completed_email.html.erb
+++ b/app/views/submitter_mailer/completed_email.html.erb
@@ -2,6 +2,6 @@
   <%= render 'custom_content', content: @body, submitter: @submitter %>
 <% else %>
   <p><%= t('hi_there') %>,</p>
-  <p><%= I18n.t(:name_has_been_completed_by_submitters, name: @submitter.submission.template.name, submitters: @submitter.submission.submitters.order(:completed_at).map { |e| e.name || e.email || e.phone }.join(', ')) %></p>
+  <p><%= I18n.t(:name_has_been_completed_by_submitters, name: @submitter.submission.template.name, submitters: @submitter.submission.submitters.order(:completed_at).map { |e| e.name || e.email || e.phone }.uniq.join(', ')) %></p>
   <p><%= link_to submission_url(@submitter.submission), submission_url(@submitter.submission) %></p>
 <% end %>
diff --git a/lib/replace_email_variables.rb b/lib/replace_email_variables.rb
index 572fd0a4..430b5757 100644
--- a/lib/replace_email_variables.rb
+++ b/lib/replace_email_variables.rb
@@ -92,6 +92,6 @@ module ReplaceEmailVariables
   end
 
   def build_submission_submitters(submission)
-    submission.submitters.order(:completed_at).map { |e| e.name || e.email || e.phone }.join(', ')
+    submission.submitters.order(:completed_at).map { |e| e.name || e.email || e.phone }.uniq.join(', ')
   end
 end