The Wireless Spectrum R&D (WSRD) Interagency Working Group (IWG) held a workshop, Radio Receiver Systems: R&D Innovation Needs and Impacts on Technology and Policy, on May 5, 2017, in Washington, D.C. At this workshop, Federal, private, and academic stakeholders discussed their individual views regarding the need for innovation in radio receiver systems. This workshop report outlines research topics that were discussed by a cross-section of experts with the goal of improving radio receiver systems. Past efforts to achieve better performance and more efficient spectrum use have focused on frequency-division and time-division allocations, but the explosion of wireless data service applications is driving the need for innovative changes in modern radio systems. Many systems are moving to wideband performance characteristics to increase their capabilities and performance. This reliance on wideband spectrum in the lower spectrum bands and the high-frequency millimeter wave bands requires designing and developing radio systems with increased functionality in both the transmitters and receivers. Improving overall system performance depends heavily on receivers being designed and built to deal with increased spectrum congestion and interference. Receiver design also needs to consider the full radio system to fully characterize and quantify performance. Upfront system engineering is needed for improved coexistence approaches that reduce overall interference. In addition, designers must balance performance metrics (e.g., sensitivity, selectivity, and efficiency) against costs, and policymakers must find ways to facilitate improved performance and information exchange that is both secure and private...