Psychology studies have shown that students' beliefs about their own intelligence--whether they view intelligence as fixed or malleable-have an important influence on student development and achievement. Yet the impact of these theories on success in Computer Science (CS) has not been directly investigated. Self-theories research has shown that students with a fixed mindset are more likely to exhibit a helpless response to substantial challenges and to experience decreases in self-esteem during college. Those with a growth mindset welcome challenges, displaying a mastery-oriented response, and maintaining self-esteem, primarily because they attribute failure to a lack of effort rather than a lack of intellectual ability. This paper introduces self-theories research, and relates this research to several issues in CS Education. We then make suggestions for how CS educators can consider self-theories in their teaching and research.