diff --git a/app/models/spree/product_decorator.rb b/app/models/spree/product_decorator.rb
index b9d45c4039..18220aaafd 100644
--- a/app/models/spree/product_decorator.rb
+++ b/app/models/spree/product_decorator.rb
@@ -38,6 +38,7 @@ Spree::Product.class_eval do
   before_validation :sanitize_permalink
   before_save :add_primary_taxon_to_taxons
   after_touch :touch_distributors
+  after_save :remove_previous_primary_taxon_from_taxons
   after_save :ensure_standard_variant
   after_save :update_units
   after_save :refresh_products_cache
@@ -245,6 +246,11 @@ Spree::Product.class_eval do
     taxons << primary_taxon unless taxons.include? primary_taxon
   end
 
+  def remove_previous_primary_taxon_from_taxons
+    return unless primary_taxon_id_changed? && primary_taxon_id_was
+    taxons.destroy(primary_taxon_id_was)
+  end
+
   def self.all_variant_unit_option_types
     Spree::OptionType.where('name LIKE ?', 'unit_%%')
   end
diff --git a/spec/models/spree/product_spec.rb b/spec/models/spree/product_spec.rb
index bf443bf2b9..f90de704e2 100644
--- a/spec/models/spree/product_spec.rb
+++ b/spec/models/spree/product_spec.rb
@@ -193,6 +193,22 @@ module Spree
           expect { product.delete }.to change { distributor.reload.updated_at }
         end
       end
+
+      it "adds the primary taxon to the product's taxon list" do
+        taxon = create(:taxon)
+        product = create(:product, primary_taxon: taxon)
+
+        expect(product.taxons).to include(taxon)
+      end
+
+      it "removes the previous primary taxon from the taxon list" do
+        original_taxon = create(:taxon)
+        product = create(:product, primary_taxon: original_taxon)
+        product.primary_taxon = create(:taxon)
+        product.save!
+
+        expect(product.taxons).not_to include(original_taxon)
+      end
     end
 
     describe "scopes" do