This article clarifies two sources of ambiguity surrounding the relation between extraversion and positive affect. First, positive affect is defined differently across major models of the structure of affect. Second, no previous research has examined potentially diverging associations of lower-order aspects of extraversion (i.e., assertiveness and enthusiasm) with positive affect. Australian (Study 1: N=437, 78% female, Mage=20.41) and American (Study 2: N=262, 39% female, Mage=33.86) participants completed multiple measures of extraversion and positive affect. Correlations were employed to examine relations among these measures. In both studies, extraversion was most clearly associated with positive affect as conceptualized within a major factor model of affect-specifically, as positive activation (Watson & Tellegen, 1985)-rather than the valence-based conceptualization of positive affect provided by a circumplex model of affect (Russell, 1980). This was also the case for the assertiveness and enthusiasm aspects of extraversion. Our findings clarify the nature of the positive affective component of extraversion, which is best described in terms of both positive valence and high activation.