In this article, we address the question of why computing students choose to learn computing topics on their own. A better understanding of why some students choose to learn on their own may help us to motivate other students to develop this important skill. In addition, it may help in curriculum design; if we need to leave some topics out of our expanding curriculum, a good choice might be those topics that students readily learn on their own. Based on a thematic analysis of 17 semistructured interviews, we found that computing students' motivations for self-directed learning fall into four general themes: projects, social and peer interactions, joy of learning, and fear. Under these, we describe several more specific subthemes, illustrated in the words of the students. The project-related and social motivations are quite prominent. Although these motivations appear in the literature, they received greater emphasis from our interviewees. Perhaps most characteristic of computing is the motivation to learn to complete some project, both projects done for fun and projects required for school or work.