The present research tested Langer’s theory of mindfulness in the context of positive experiences: positive state mindfulness. In Study 1 (N1 = 586, N2 = 415) confirmatory factor analyses indicated that a three-factor model (Focused Attention, Novelty Appreciation, Open-Ended Expectations) fit the data well and explained responses better than a one-factor model. In support of construct validity, Study 2 (N3 = 239, N4 = 126) suggested that each dimension had a different pattern of associations with unidimensional trait measures of mindfulness, savoring beliefs, trait absorption, uncertainty tolerance, need for structure, and need for cognition. Study 3 (N5 = 46) revealed that each dimension correlated uniquely with the positive affect, self-esteem, interpersonal connectedness, and the overall rehearsal frequency associated with positive autobiographical events. In support of criterion validity in Study 4, in Experiment 1 (N6 = 46) a boredom task decreased Novelty Appreciation, and in Experiment 2 (N7 = 92) a problem-solving task increased Focused Attention. Our data suggest that positive mindfulness is more than the absence of mindlessness and that it includes three distinct dimensions. We discuss the utility of positive mindfulness in both research and practice.