diff --git a/app/models/spree/order.rb b/app/models/spree/order.rb
index 817a0d716b..556b8b0c13 100644
--- a/app/models/spree/order.rb
+++ b/app/models/spree/order.rb
@@ -293,6 +293,8 @@ module Spree
     # Creates new tax charges if there are any applicable rates. If prices already
     # include taxes then price adjustments are created instead.
     def create_tax_charge!
+      clear_legacy_taxes!
+
       Spree::TaxRate.adjust(self, line_items)
       Spree::TaxRate.adjust(self, shipments) if shipments.any?
       Spree::TaxRate.adjust(self, all_adjustments.enterprise_fee)
@@ -592,6 +594,13 @@ module Spree
       @fee_handler ||= OrderFeesHandler.new(self)
     end
 
+    def clear_legacy_taxes!
+      # For instances that use additional taxes, old orders can have taxes recorded in
+      # lump-sum amounts per-order. We clear them here before re-applying the order's taxes,
+      # which will now be applied per-item.
+      adjustments.tax.additional.delete_all
+    end
+
     def process_each_payment
       raise Core::GatewayError, Spree.t(:no_pending_payments) if pending_payments.empty?