diff --git a/app/models/inbox.rb b/app/models/inbox.rb
index 802346f7f..890e8b151 100644
--- a/app/models/inbox.rb
+++ b/app/models/inbox.rb
@@ -51,6 +51,7 @@ class Inbox < ApplicationRecord
   validates :account_id, presence: true
   validates :timezone, inclusion: { in: TZInfo::Timezone.all_identifiers }
   validates :out_of_office_message, length: { maximum: Limits::OUT_OF_OFFICE_MESSAGE_MAX_LENGTH }
+  validates :greeting_message, length: { maximum: Limits::GREETING_MESSAGE_MAX_LENGTH }
   validate :ensure_valid_max_assignment_limit
 
   belongs_to :account
diff --git a/lib/limits.rb b/lib/limits.rb
index b375d2759..720f302a8 100644
--- a/lib/limits.rb
+++ b/lib/limits.rb
@@ -3,4 +3,5 @@ module Limits
   BULK_EXTERNAL_HTTP_CALLS_LIMIT = 25
   URL_LENGTH_LIMIT = 2048 # https://stackoverflow.com/questions/417142
   OUT_OF_OFFICE_MESSAGE_MAX_LENGTH = 10_000
+  GREETING_MESSAGE_MAX_LENGTH = 10_000
 end