diff --git a/app/jobs/onceoff/migrate_from_slack_official.rb b/app/jobs/onceoff/migrate_from_slack_official.rb
index 19c9b4c..f250efd 100644
--- a/app/jobs/onceoff/migrate_from_slack_official.rb
+++ b/app/jobs/onceoff/migrate_from_slack_official.rb
@@ -62,6 +62,7 @@ module Jobs
 
       rows.each do |row|
         # Load an existing channel with this identifier. If none, create it
+        row[:channel] = "##{row[:channel]}" unless row[:channel].start_with?("#")
         channel = DiscourseChat::Channel.with_provider('slack').with_data_value('identifier', row[:channel]).first
         if !channel
           channel = DiscourseChat::Channel.create(provider: 'slack', data: { identifier: row[:channel] })
diff --git a/spec/jobs/onceoff/migrate_from_slack_official_spec.rb b/spec/jobs/onceoff/migrate_from_slack_official_spec.rb
index 715e455..534b7ea 100644
--- a/spec/jobs/onceoff/migrate_from_slack_official_spec.rb
+++ b/spec/jobs/onceoff/migrate_from_slack_official_spec.rb
@@ -62,7 +62,7 @@ RSpec.describe Jobs::DiscourseChatMigrateFromSlackOfficial do
         plugin_name: 'discourse-slack-official',
         key: "category_*",
         type_name: "JSON",
-        value: "[{\"channel\":\"#channel1\",\"filter\":\"watch\"},{\"channel\":\"#channel2\",\"filter\":\"follow\"},{\"channel\":\"#channel1\",\"filter\":\"mute\"}]"
+        value: "[{\"channel\":\"#channel1\",\"filter\":\"watch\"},{\"channel\":\"channel2\",\"filter\":\"follow\"},{\"channel\":\"#channel1\",\"filter\":\"mute\"}]"
       )
     end