We conduct a thematic analysis of a U.S. adult sample’s self-reported motives and perception of environmental activists’ motives to engage in pro-environmental behavior via a qualitative online survey. We identified themes using a two-stage coding procedure, whereby the research team first helped to code all content into one or more of 17 inductive content categories, then the lead investigator examined themes in each of the categories and created 5 themes based on both inductive and theoretical (e.g., moral foundations theory) considerations: a) harm and care, b) purity, c) waste and efficiency, d) spreading awareness, and e) self-interest (mostly non-financial). Endorsement of themes were qualitatively similar across individuals’ own self-described motives and perceptions of environmental activists’ motives.