diff --git a/app/models/customer.rb b/app/models/customer.rb
index 6bbd4606e5..856f7e94d7 100644
--- a/app/models/customer.rb
+++ b/app/models/customer.rb
@@ -9,4 +9,12 @@ class Customer < ActiveRecord::Base
   validates :enterprise_id, presence: true
 
   scope :of, ->(enterprise) { where(enterprise_id: enterprise) }
+
+  before_create :associate_user
+
+  private
+
+  def associate_user
+    self.user = user || Spree::User.find_by_email(email)
+  end
 end
diff --git a/app/models/spree/order_decorator.rb b/app/models/spree/order_decorator.rb
index 0dc6977965..28a8007da6 100644
--- a/app/models/spree/order_decorator.rb
+++ b/app/models/spree/order_decorator.rb
@@ -10,11 +10,14 @@ Spree::Order.class_eval do
   belongs_to :order_cycle
   belongs_to :distributor, :class_name => 'Enterprise'
   belongs_to :cart
+  belongs_to :customer
 
+  validates :customer, presence: true, if: :require_customer?
   validate :products_available_from_new_distribution, :if => lambda { distributor_id_changed? || order_cycle_id_changed? }
   attr_accessible :order_cycle_id, :distributor_id
 
   before_validation :shipping_address_from_distributor
+  before_validation :associate_customer, unless: :customer_is_valid?
 
   checkout_flow do
     go_to_state :address
@@ -260,4 +263,24 @@ Spree::Order.class_eval do
   def product_distribution_for(line_item)
     line_item.variant.product.product_distribution_for self.distributor
   end
+
+  def require_customer?
+    return true unless new_record? or state == 'cart'
+  end
+
+  def customer_is_valid?
+    return true unless require_customer?
+    customer.present? && customer.enterprise_id == distributor_id && customer.email == (user.andand.email || email)
+  end
+
+  def associate_customer
+    email_for_customer = user.andand.email || email
+    existing_customer = Customer.of(distributor).find_by_email(email_for_customer)
+    if existing_customer
+      self.customer = existing_customer
+    else
+      new_customer = Customer.create(enterprise: distributor, email: email_for_customer, user: user)
+      self.customer = new_customer
+    end
+  end
 end
diff --git a/spec/models/customer_spec.rb b/spec/models/customer_spec.rb
new file mode 100644
index 0000000000..0e43ce9df5
--- /dev/null
+++ b/spec/models/customer_spec.rb
@@ -0,0 +1,20 @@
+require 'spec_helper'
+
+describe Customer, type: :model do
+  describe 'creation callbacks' do
+    let!(:user1) { create(:user) }
+    let!(:user2) { create(:user) }
+    let!(:enterprise) { create(:distributor_enterprise) }
+
+    it "associates an existing user using email" do
+      c1 = Customer.create(enterprise: enterprise, email: 'some-email-not-associated-with-a-user@email.com')
+      expect(c1.user).to be_nil
+
+      c2 = Customer.create(enterprise: enterprise, email: 'some-email-not-associated-with-a-user@email.com', user: user1)
+      expect(c2.user).to eq user1
+
+      c3 = Customer.create(enterprise: enterprise, email: user2.email)
+      expect(c3.user).to eq user2
+    end
+  end
+end
diff --git a/spec/models/spree/order_spec.rb b/spec/models/spree/order_spec.rb
index ecc19f5493..dddaf554a2 100644
--- a/spec/models/spree/order_spec.rb
+++ b/spec/models/spree/order_spec.rb
@@ -511,4 +511,43 @@ describe Spree::Order do
       end.to enqueue_job ConfirmOrderJob
     end
   end
+
+  describe "associating a customer" do
+    let(:user) { create(:user) }
+    let(:distributor) { create(:distributor_enterprise) }
+
+    context "when a user has been set on the order" do
+      let!(:order) { create(:order, distributor: distributor, user: user) }
+      context "and a customer for order.distributor and order.user.email already exists" do
+        let!(:customer) { create(:customer, enterprise: distributor, email: user.email) }
+        it "associates the order with the existing customer" do
+          order.send(:associate_customer)
+          expect(order.customer).to eq customer
+        end
+      end
+      context "and a customer for order.distributor and order.user.email does not alread exist" do
+        let!(:customer) { create(:customer, enterprise: distributor, email: 'some-other-email@email.com') }
+        it "creates a new customer" do
+          expect{order.send(:associate_customer)}.to change{Customer.count}.by 1
+        end
+      end
+    end
+
+    context "when a user has not been set on the order" do
+      let!(:order) { create(:order, distributor: distributor, user: nil) }
+      context "and a customer for order.distributor and order.email already exists" do
+        let!(:customer) { create(:customer, enterprise: distributor, email: order.email) }
+        it "creates a new customer" do
+          order.send(:associate_customer)
+          expect(order.customer).to eq customer
+        end
+      end
+      context "and a customer for order.distributor and order.email does not alread exist" do
+        let!(:customer) { create(:customer, enterprise: distributor, email: 'some-other-email@email.com') }
+        it "creates a new customer" do
+          expect{order.send(:associate_customer)}.to change{Customer.count}.by 1
+        end
+      end
+    end
+  end
 end