Previous research suggests that nonmonosexual individuals engage in complex patterns of sexual orientation self-presentation, which may be obscured by traditional measures of disclosure and concealment. This study used an experience-sampling design to examine 165 nonmonosexual cisgender women’s day-to-day self-presentation experiences using the novel framework of self-presentational accuracy. Participants demonstrated substantial within-person variability in self-presentational accuracy. Several contextual factors (e.g., anticipated acceptance, interaction partner sexual orientation) predicted self-presentational accuracy at the within-person level, and several person-level factors (e.g., outness, internalized monosexism) predicted self-presentational accuracy at the between-person level. Furthermore, self-presentational accuracy predicted same-day life satisfaction and positive affect through the mediator of social support at the within-person level. Contrary to my hypotheses, self-presentational accuracy was unrelated to romantic partner gender and to negative affect. Overall, results suggested that nonmonosexual women are sensitive to context when making sexual orientation self-presentation decisions, and that these decisions influence their day-to-day well-being.