Global smartphone shipments declined -2% YoY to 345 million units in Q1 2018. Android maintained the leading position but slightly lost ground to iOS. All other platforms lost traction. Our extensive report contains global smartphone shipments by operating system by quarter from Q1 2008 to Q1 2018. A pivot table and flat file of smartphone shipment by vendor by OS by region from Q1 2008 through Q1 2018 are included too. The report is valuable for mobile stakeholders who want to size the huge market for smartphones and operating system market share.