News Framing Effects is a guide to effects theory, one of the most prominent theories in media and communication science. Rooted in both psychology and sociology, effects theory describes the ability of media to influence people’s attitudes and behaviors by subtle changes to how they report on an issue. The book gives expert commentary on this complex theoretical notion alongside practical instruction on how to apply it to research. The book’s structure mirrors the steps a scholar might take to design a study. The first chapter establishes a working definition of effects theory. The following chapters focus on how to identify the independent variable (i.e., the news frame) and the dependent variable (i.e., the framing effect). The book then considers the potential limits or enhancements of the proposed effects (i.e., the moderators) and how effects might emerge (i.e., the mediators). Finally, it asks how strong these effects are likely to be. The final chapter considers research in the light of a rapidly and fundamentally changing and information market, in which technologies, platforms, and changing consumption patterns are forcing assumptions at the core of effects theory to be re-evaluated.