Background: Cocurricular and extracurricular activities benefit precollege students. Yet connections between these activities and academic outcomes in college are mixed or inconclusive. Little is known about how involvement in cocurricular activities is associated specifically with academic engagement in college. Purpose (Hypothesis): The purpose of this study was to understand the connection between cocurricular activities and academic engagement for engineering and computer science undergraduates. We hypothesized that cocurricular activities and engagement are not directly related but are associated with one another through interactions with academic self-efficacy. Design/Method: This study surveyed engineering and computer science students at four different institutions. Data were analyzed using multiple linear regression models to understand the relationships between cocurricular activities and academic engagement. Results: While relationships between cocurricular activities and academic engagement were not significant, interaction effects with academic self-efficacy were significant. Academic cocurricular activities interacted positively with, whereas nonacademic cocurricular activities interacted negatively with, relationships between self-efficacy and academic engagement. Conclusions: Results show that connections between cocurricular involvement and academic engagement not only occur in interactions with self-efficacy, but also depend on the nature of the cocurricular activity. Most students who are active in cocurricular activities report higher levels of engagement than do their nonactive peers for the same levels of self-efficacy.