diff --git a/app/models/post.rb b/app/models/post.rb
index 7aa9155264a..3f97171bb79 100644
--- a/app/models/post.rb
+++ b/app/models/post.rb
@@ -63,6 +63,7 @@ class Post < ActiveRecord::Base
   has_many :post_hotlinked_media, dependent: :destroy, class_name: "PostHotlinkedMedia"
 
   validates_with PostValidator, unless: :skip_validation
+  validates :edit_reason, length: { maximum: 1000 }
 
   after_commit :index_search
 
diff --git a/spec/models/post_spec.rb b/spec/models/post_spec.rb
index deb5e637f9e..d4327035441 100644
--- a/spec/models/post_spec.rb
+++ b/spec/models/post_spec.rb
@@ -57,6 +57,7 @@ RSpec.describe Post do
   end
 
   it { is_expected.to validate_presence_of :raw }
+  it { is_expected.to validate_length_of(:edit_reason).is_at_most(1000) }
 
   # Min/max body lengths, respecting padding
   it { is_expected.not_to allow_value("x").for(:raw) }