Recent calls in environmental communication literature suggest researchers should understand the relationships between media message content, message construction, and audience effects. This thesis analyzed environmental advertising frames over time to inform strategic environmental communication research and practice. The study was a media content analysis guided by framing theory. Framing theory asserts the construction of media messages involves the selection and salience of particular message characteristics (Entman, 1993). Thus, the analysis examined the characteristics of environmental advertisements (N=449) published in Newsweek, Time, and U.S. News and World Report in 1990, 2000, and 2010. Advertisements were classified based on whether the environmental appeal was issue-specific (e.g., pollution, species/habitat protection) or generic. Findings indicate that responsibility frames were overwhelmingly dominant as the strategy used to advertise products, goods and services. The responsibility frame was also prevalent in issue-specific ads. Macro-frames, which attempt to identify organizing lenses through which environmental advertising appeals are advanced, were not present in advertisements at significant levels during the time periods analyzed. The species/habitat protection issue was the dominant issue in 1990, while energy efficiency was the prevalent issue in 2000 and 2010. Advertisements appearing in the newsmagazine pages primarily were sponsored by for-profit organizations. Environmental advertisements had an overwhelmingly positive valence over time. Results have implications for future environmental communication research exploring media content and effects, public opinion and persuasion, and strategic communication practice. / Master of Arts