diff --git a/app/models/spree/variant.rb b/app/models/spree/variant.rb
index 6fc36cc27c..94e3bfb3c5 100644
--- a/app/models/spree/variant.rb
+++ b/app/models/spree/variant.rb
@@ -83,6 +83,7 @@ module Spree
     before_validation :ensure_unit_value
     before_validation :update_weight_from_unit_value, if: ->(v) { v.product.present? }
     before_validation :convert_variant_weight_to_decimal
+    before_validation :assign_related_taxon, if: ->(v) { v.primary_taxon.blank? }
 
     before_save :assign_units, if: ->(variant) {
       variant.new_record? || variant.changed_attributes.keys.intersection(NAME_FIELDS).any?
@@ -209,6 +210,10 @@ module Spree
 
     private
 
+    def assign_related_taxon
+      self.primary_taxon ||= product.variants.last&.primary_taxon
+    end
+
     def check_currency
       return unless currency.nil?