Studies of the grant proposal tend to conflate academic research grant proposals with other kinds of nonprofit grant proposal genres, even though research and nonprofit grant proposals have different audiences and goals. To address this gap, this study draws on the Aristotelian concept of "topoi" (or typical arguments) and uses corpus analysis, interview, and coding methods to answer the question, what "topoi" distinguish the academic research and nonprofit grant proposal genres? Findings suggest key differences in the "topoi" that research and nonprofit proposals use to advocate for problems and outcomes, set goals, and establish credibility.