diff --git a/lib/stripe_mock/request_handlers/customers.rb b/lib/stripe_mock/request_handlers/customers.rb
index c35930bc2..4928715df 100644
--- a/lib/stripe_mock/request_handlers/customers.rb
+++ b/lib/stripe_mock/request_handlers/customers.rb
@@ -40,7 +40,7 @@ def new_customer(route, method_url, params, headers)
           end
 
           subscription = Data.mock_subscription({ id: new_id('su') })
-          subscription.merge!(custom_subscription_params(plan, customers[ params[:id] ], params))
+          subscription = resolve_subscription_changes(subscription, [plan], customers[ params[:id] ], params)
           add_subscription_to_customer(customers[ params[:id] ], subscription)
           subscriptions[subscription[:id]] = subscription
         elsif params[:trial_end]
diff --git a/lib/stripe_mock/request_handlers/helpers/subscription_helpers.rb b/lib/stripe_mock/request_handlers/helpers/subscription_helpers.rb
index d63c4f4b5..14df93f23 100644
--- a/lib/stripe_mock/request_handlers/helpers/subscription_helpers.rb
+++ b/lib/stripe_mock/request_handlers/helpers/subscription_helpers.rb
@@ -6,13 +6,22 @@ def get_customer_subscription(customer, sub_id)
         customer[:subscriptions][:data].find{|sub| sub[:id] == sub_id }
       end
 
-      def custom_subscription_params(plan, cus, options = {})
+      def resolve_subscription_changes(subscription, plans, customer, options = {})
+        subscription.merge!(custom_subscription_params(plans, customer, options))
+        subscription[:items][:data] = plans.map { |plan| Data.mock_subscription_item({ plan: plan }) }
+        subscription
+      end
+
+      def custom_subscription_params(plans, cus, options = {})
         verify_trial_end(options[:trial_end]) if options[:trial_end]
 
+        plan = plans.first if plans.size == 1
+
         now = Time.now.utc.to_i
         created_time = options[:created] || now
         start_time = options[:current_period_start] || now
-        params = { plan: plan, customer: cus[:id], current_period_start: start_time, created: created_time }
+        params = { customer: cus[:id], current_period_start: start_time, created: created_time }
+        params.merge!({ :plan => (plans.size == 1 ? plans.first : nil) })
         params.merge! options.select {|k,v| k =~ /application_fee_percent|quantity|metadata|tax_percent/}
         # TODO: Implement coupon logic
 
@@ -87,14 +96,6 @@ def total_items_amount(items)
         items.each { |i| total += (i[:quantity] || 1) * i[:plan][:amount] }
         total
       end
-
-      def mock_subscription_items(items = [])
-        data = []
-        items.each do |i|
-          data << Data.mock_subscription_item(i.merge(plan: plans[i[:plan].to_s]))
-        end
-        data
-      end
     end
   end
 end
diff --git a/lib/stripe_mock/request_handlers/invoices.rb b/lib/stripe_mock/request_handlers/invoices.rb
index 8f8e242bc..3e4434082 100644
--- a/lib/stripe_mock/request_handlers/invoices.rb
+++ b/lib/stripe_mock/request_handlers/invoices.rb
@@ -87,7 +87,7 @@ def upcoming_invoice(route, method_url, params, headers)
           invoice_date = Time.now.to_i
           subscription_plan = assert_existence :plan, subscription_plan_id, plans[subscription_plan_id.to_s]
           preview_subscription = Data.mock_subscription
-          preview_subscription.merge!(custom_subscription_params(subscription_plan, customer, { trial_end: params[:subscription_trial_end] }))
+          preview_subscription = resolve_subscription_changes(preview_subscription, [subscription_plan], customer, { trial_end: params[:subscription_trial_end] })
           preview_subscription[:id] = subscription[:id]
           preview_subscription[:quantity] = subscription_quantity
           subscription_proration_date = params[:subscription_proration_date] || Time.now
diff --git a/lib/stripe_mock/request_handlers/subscriptions.rb b/lib/stripe_mock/request_handlers/subscriptions.rb
index 28933c1e9..8a4fbd192 100644
--- a/lib/stripe_mock/request_handlers/subscriptions.rb
+++ b/lib/stripe_mock/request_handlers/subscriptions.rb
@@ -32,24 +32,10 @@ def retrieve_customer_subscriptions(route, method_url, params, headers)
         customer[:subscriptions]
       end
 
-      def plan_id_from_params(params)
-        if params[:plan]
-          params[:plan].to_s
-        elsif params[:items]
-          item = params[:items].values.find { |item| item[:plan] }
-          if item
-            item[:plan].to_s
-          end
-        end
-      end
-
       def create_customer_subscription(route, method_url, params, headers)
         route =~ method_url
 
-        plan_id = plan_id_from_params(params)
-
-        plan = assert_existence :plan, plan_id, plans[plan_id]
-
+        subscription_plans = get_subscription_plans_from_params(params)
         customer = assert_existence :customer, $1, customers[$1]
 
         if params[:source]
@@ -59,10 +45,11 @@ def create_customer_subscription(route, method_url, params, headers)
         end
 
         subscription = Data.mock_subscription({ id: (params[:id] || new_id('su')) })
-        subscription.merge!(custom_subscription_params(plan, customer, params))
+        subscription = resolve_subscription_changes(subscription, subscription_plans, customer, params)
 
         # Ensure customer has card to charge if plan has no trial and is not free
-        verify_card_present(customer, plan, subscription, params)
+        # Note: needs updating for subscriptions with multiple plans
+        verify_card_present(customer, subscription_plans.first, subscription, params)
 
         if params[:coupon]
           coupon_id = params[:coupon]
@@ -82,25 +69,23 @@ def create_customer_subscription(route, method_url, params, headers)
         subscriptions[subscription[:id]] = subscription
         add_subscription_to_customer(customer, subscription)
 
-        clear_top_level_plan_if_multiple_items(subscription)
-
         subscriptions[subscription[:id]]
       end
 
       def create_subscription(route, method_url, params, headers)
         route =~ method_url
 
-        plan_id = plan_id_from_params(params)
-
-        plan = plan_id ? assert_existence(:plan, plan_id, plans[plan_id]) : nil
+        subscription_plans = get_subscription_plans_from_params(params)
 
         customer = params[:customer]
         customer_id = customer.is_a?(Stripe::Customer) ? customer[:id] : customer.to_s
         customer = assert_existence :customer, customer_id, customers[customer_id]
 
-        if plan && customer
-          unless customer[:currency].to_s == plan[:currency].to_s
-            raise Stripe::InvalidRequestError.new('lol', 'currency', http_status: 400)
+        if subscription_plans && customer
+          subscription_plans.each do |plan|
+            unless customer[:currency].to_s == plan[:currency].to_s
+              raise Stripe::InvalidRequestError.new('lol', 'currency', http_status: 400)
+            end
           end
         end
 
@@ -117,11 +102,11 @@ def create_subscription(route, method_url, params, headers)
         end
 
         subscription = Data.mock_subscription({ id: (params[:id] || new_id('su')) })
-        subscription.merge!(custom_subscription_params(plan, customer, params))
-        subscription[:items][:data] = mock_subscription_items(params[:items].values) if params[:items]
+        subscription = resolve_subscription_changes(subscription, subscription_plans, customer, params)
 
         # Ensure customer has card to charge if plan has no trial and is not free
-        verify_card_present(customer, plan, subscription, params)
+        # Note: needs updating for subscriptions with multiple plans
+        verify_card_present(customer, subscription_plans.first, subscription, params)
 
         if params[:coupon]
           coupon_id = params[:coupon]
@@ -141,8 +126,6 @@ def create_subscription(route, method_url, params, headers)
         subscriptions[subscription[:id]] = subscription
         add_subscription_to_customer(customer, subscription)
 
-        clear_top_level_plan_if_multiple_items(subscription)
-
         subscriptions[subscription[:id]]
       end
 
@@ -176,21 +159,12 @@ def update_subscription(route, method_url, params, headers)
           customer[:default_source] = new_card[:id]
         end
 
-        # expand the plan for addition to the customer object
-        plan_id = plan_id_from_params(params)
-
-        unless plan_id
-          plan_id = if subscription[:plan]
-                      subscription[:plan][:id]
-                    elsif subscription[:items]
-                      row = subscription[:items][:data].find { |item| item[:plan] }
-                      if row
-                        row[:plan][:id]
-                      end
-                    end
-        end
+        subscription_plans = get_subscription_plans_from_params(params)
 
-        plan = plans[plan_id]
+        # subscription plans are not being updated but load them for the response
+        if subscription_plans.empty?
+          subscription_plans = subscription[:items][:data].map { |item| item[:plan] }
+        end
 
         if params[:coupon]
           coupon_id = params[:coupon]
@@ -207,10 +181,7 @@ def update_subscription(route, method_url, params, headers)
             raise Stripe::InvalidRequestError.new("No such coupon: #{coupon_id}", 'coupon', http_status: 400)
           end
         end
-
-        assert_existence :plan, plan_id, plan
-        params[:plan] = plan if params[:plan]
-        verify_card_present(customer, plan, subscription)
+        verify_card_present(customer, subscription_plans.first, subscription)
 
         if subscription[:cancel_at_period_end]
           subscription[:cancel_at_period_end] = false
@@ -218,14 +189,12 @@ def update_subscription(route, method_url, params, headers)
         end
 
         params[:current_period_start] = subscription[:current_period_start]
-        subscription.merge!(custom_subscription_params(plan, customer, params))
+        subscription = resolve_subscription_changes(subscription, subscription_plans, customer, params)
 
         # delete the old subscription, replace with the new subscription
         customer[:subscriptions][:data].reject! { |sub| sub[:id] == subscription[:id] }
         customer[:subscriptions][:data] << subscription
 
-        clear_top_level_plan_if_multiple_items(subscription)
-
         subscription
       end
 
@@ -259,8 +228,20 @@ def cancel_subscription(route, method_url, params, headers)
 
       private
 
-      def clear_top_level_plan_if_multiple_items(subscription)
-        subscription[:plan] = nil if subscription[:items][:data].size > 1
+      def get_subscription_plans_from_params(params)
+        plan_ids = if params[:plan]
+                     [params[:plan].to_s]
+                   elsif params[:items]
+                     items = params[:items]
+                     items = items.values if items.respond_to?(:values)
+                     items.map { |item| item[:plan].to_s if item[:plan] }
+                   else
+                     []
+                   end
+        plan_ids.each do |plan_id|
+          assert_existence :plan, plan_id, plans[plan_id]
+        end
+        plan_ids.map { |plan_id| plans[plan_id] }
       end
 
       def verify_card_present(customer, plan, subscription, params={})
diff --git a/spec/shared_stripe_examples/subscription_examples.rb b/spec/shared_stripe_examples/subscription_examples.rb
index e5ba12dcb..6f3dd9d51 100644
--- a/spec/shared_stripe_examples/subscription_examples.rb
+++ b/spec/shared_stripe_examples/subscription_examples.rb
@@ -504,6 +504,57 @@ def gen_card_tk
       expect(customer.subscriptions.data.first.customer).to eq(customer.id)
     end
 
+    it "updates a stripe customer's existing subscription with single plan when multiple plans inside of items" do
+      silver_plan = stripe_helper.create_plan(id: 'silver')
+      gold_plan = stripe_helper.create_plan(id: 'gold')
+      addon_plan = stripe_helper.create_plan(id: 'addon_plan')
+      customer = Stripe::Customer.create(id: 'test_customer_sub', source: gen_card_tk, plan: silver_plan.id)
+
+      sub = Stripe::Subscription.retrieve(customer.subscriptions.data.first.id)
+      sub.items = [{ plan: gold_plan.id, quantity: 2 }, { plan: addon_plan.id, quantity: 2 }]
+      expect(sub.save).to be_truthy
+
+      expect(sub.object).to eq('subscription')
+      expect(sub.plan).to be_nil
+
+      customer = Stripe::Customer.retrieve('test_customer_sub')
+      expect(customer.subscriptions.data).to_not be_empty
+      expect(customer.subscriptions.count).to eq(1)
+      expect(customer.subscriptions.data.length).to eq(1)
+
+      expect(customer.subscriptions.data.first.id).to eq(sub.id)
+      expect(customer.subscriptions.data.first.plan).to be_nil
+      expect(customer.subscriptions.data.first.customer).to eq(customer.id)
+      expect(customer.subscriptions.data.first.items.data[0].plan.to_hash).to eq(gold_plan.to_hash)
+      expect(customer.subscriptions.data.first.items.data[1].plan.to_hash).to eq(addon_plan.to_hash)
+    end
+
+    it "updates a stripe customer's existing subscription with multple plans when multiple plans inside of items" do
+      silver_plan = stripe_helper.create_plan(id: 'silver')
+      gold_plan = stripe_helper.create_plan(id: 'gold')
+      addon1_plan = stripe_helper.create_plan(id: 'addon1')
+      addon2_plan = stripe_helper.create_plan(id: 'addon2')
+      customer = Stripe::Customer.create(id: 'test_customer_sub', source: gen_card_tk)
+      sub = Stripe::Subscription.create(customer: customer.id, items: [{ plan: silver_plan.id }, { plan: addon1_plan.id }])
+
+      sub.items = [{ plan: gold_plan.id, quantity: 2 }, { plan: addon2_plan.id, quantity: 2 }]
+      expect(sub.save).to be_truthy
+
+      expect(sub.object).to eq('subscription')
+      expect(sub.plan).to be_nil
+
+      customer = Stripe::Customer.retrieve('test_customer_sub')
+      expect(customer.subscriptions.data).to_not be_empty
+      expect(customer.subscriptions.count).to eq(1)
+      expect(customer.subscriptions.data.length).to eq(1)
+
+      expect(customer.subscriptions.data.first.id).to eq(sub.id)
+      expect(customer.subscriptions.data.first.plan).to be_nil
+      expect(customer.subscriptions.data.first.customer).to eq(customer.id)
+      expect(customer.subscriptions.data.first.items.data[0].plan.to_hash).to eq(gold_plan.to_hash)
+      expect(customer.subscriptions.data.first.items.data[1].plan.to_hash).to eq(addon2_plan.to_hash)
+    end
+
     it 'when adds coupon', live: true do
       plan = stripe_helper.create_plan(id: 'plan_with_coupon2', name: 'One More Test Plan', amount: 777)
       coupon = stripe_helper.create_coupon
@@ -857,13 +908,13 @@ def gen_card_tk
       expect(subscription.items.object).to eq('list')
       expect(subscription.items.data.class).to eq(Array)
       expect(subscription.items.data.count).to eq(1)
-      expect(subscription.items.data.first.id).to eq('si_1AwFf62eZvKYlo2C9u6Dhf9')
-      expect(subscription.items.data.first.created).to eq(1504035973)
+      expect(subscription.items.data.first.id).to eq('test_txn_default')
+      expect(subscription.items.data.first.created).to eq(1504716183)
       expect(subscription.items.data.first.object).to eq('subscription_item')
-      expect(subscription.items.data.first.plan.amount).to eq(999)
-      expect(subscription.items.data.first.plan.created).to eq(1504035972)
+      expect(subscription.items.data.first.plan.amount).to eq(0)
+      expect(subscription.items.data.first.plan.created).to eq(1466698898)
       expect(subscription.items.data.first.plan.currency).to eq('usd')
-      expect(subscription.items.data.first.quantity).to eq(1)
+      expect(subscription.items.data.first.quantity).to eq(2)
     end
   end