As issues of environmental degradation become increasingly pressing and publicized, it is imperative that scholars have a clear understanding of the forces that can lead individuals to adopt pro-environmental behaviors (PEBs). Two such antecedents that have been widely studied are pro-environmental attitudes and efficacy. Although ample research has been published to explore the relationships between pro-environmental attitudes, efficacy, and PEB, the field lacks a coherent understanding of the many subdimensions of these constructs and the relationships between them. Furthermore, there is little research that explores how these constructs may vary across countries—an understanding of which is vital to combat such global phenomena. Finally, previous research indicates that media communication of environmental issues can impact environmental attitudes and pro-environmental behavior; however, further examination of various types of media use can elucidate which media measures best relate to pro-environmental attitudes and behaviors across countries. Using data from a large international survey (N = 1,000 adults in each of 12 countries) conducted in 2019 by Ipsos for the National Geographic society, this thesis attempts to clarify these central constructs of environmental communication by testing the relationships between these constructs and their subdimensions overall, and across countries.Hierarchical linear regressions revealed that a general model, using the combined measures of these constructs, provided the best option for cross-country relationships between EA, efficacy, media, and PEB. Unexpectedly, a mismatch model examining environmental concern, self-efficacy, and public PEB provided the most variance explained on the combined (cross-country) sample. Although the fit of the models to individual country samples varied substantially, country-level differences explained less unique variance in the model than pro-environmental attitudes, and similar amounts of unique variance as the other model variables and controls. The results show that environmental attitudes are a strong predictor of PEB across countries, and the direct and interactive relationships involving efficacy are very small and inconsistent across countries. The relative dominance of environmental attitudes as a predictor raises questions about the unique importance of efficacy in explaining PEB separate from attitudes. However, due to the small effect sizes and correlational nature of the data, it is unclear whether communication campaigns targeting pro-environmental attitudes can result in desired behavior change. The nuanced connections between these variables within individual countries highlight the importance of cross-national environmental research.