To address the complex and crosscutting challenges facing the federal government, agencies need to effectively engage and collaborate with those in the private, nonprofit, and academic sectors, other levels of government, and citizens. Agencies are increasingly using open innovation strategies for these purposes. The GPRA Modernization Act of 2010 (GPRAMA) requires federal agencies to identify strategies and resources they will use to achieve their goals. GPRAMA also requires GAO to periodically review how implementation of its requirements is affecting agency performance. This report identifies and illustrates practices that help agencies effectively implement open innovation strategies, and how the use of those strategies has affected agency performance and opportunities for citizen engagement. To identify these practices, GAO analyzed relevant federal guidance and academic literature, and interviewed open innovation experts. To refine and illustrate the practices, GAO reviewed documents and interviewed officials from the Office of Management and Budget, Office of Science and Technology Policy, General Services Administration, and six selected federal agencies. GAO selected the agencies and a sample of their initiatives based on several factors, including the number and type of initiatives outlined in their Open Government Plans.