Studies of framing effects are a fundamental part of media effects research. A framing effect occurs when a media frame affects audience members' understanding of or opinion about an issue. The literature suggests three psychological processes—accessibility change, belief importance change, and belief content change—that can mediate framing effects. Framing effects are moderated by individual differences such as values and political awareness and by contextual factors, including the source of the frame, competitive frame exposure, and repeated frame exposure. The future research agenda should include a clarification of the concept of framing as well as further investigation of the role of emotions, dynamic competitive framing effects, and duration of framing effects. Finally, the influence of online and social media on framing effects also constitutes an interesting area for future studies.