diff --git a/app/models/billing_entity/applied_tax.rb b/app/models/billing_entity/applied_tax.rb
index a713207a0d7..810206b5a9d 100644
--- a/app/models/billing_entity/applied_tax.rb
+++ b/app/models/billing_entity/applied_tax.rb
@@ -6,6 +6,8 @@ class AppliedTax < ApplicationRecord
 
     belongs_to :billing_entity
     belongs_to :tax
+
+    validates :tax_id, uniqueness: {scope: :billing_entity_id}
   end
 end
 
diff --git a/spec/models/billing_entity/applied_tax_spec.rb b/spec/models/billing_entity/applied_tax_spec.rb
index 8bf7fb744cd..0747edd0ac5 100644
--- a/spec/models/billing_entity/applied_tax_spec.rb
+++ b/spec/models/billing_entity/applied_tax_spec.rb
@@ -8,8 +8,5 @@
   it { is_expected.to belong_to(:billing_entity) }
   it { is_expected.to belong_to(:tax) }
 
-  it { is_expected.to validate_presence_of(:billing_entity) }
-  it { is_expected.to validate_presence_of(:tax) }
-
   it { is_expected.to validate_uniqueness_of(:tax_id).scoped_to(:billing_entity_id) }
 end