diff --git a/app/controllers/api/v1/antennas/keywords_controller.rb b/app/controllers/api/v1/antennas/keywords_controller.rb
index b35fb535dc..5260a66bc0 100644
--- a/app/controllers/api/v1/antennas/keywords_controller.rb
+++ b/app/controllers/api/v1/antennas/keywords_controller.rb
@@ -17,6 +17,7 @@ class Api::V1::Antennas::KeywordsController < Api::BaseController
     new_keywords = @antenna.keywords || []
     keywords.each do |keyword|
       raise Mastodon::ValidationError, I18n.t('antennas.errors.duplicate_keyword') if new_keywords.include?(keyword)
+      raise Mastodon::ValidationError, I18n.t('antennas.errors.too_short_keyword') if keyword.length < 2
 
       new_keywords << keyword
     end