In this chapter, the authors describe research showing that people's mindsets, or their "implicit theories," about intelligence significantly impact their academic motivation and performance, sometimes in counter-intuitive ways. In particular, accumulating evidence shows that holding a "growth mindset"—the belief in intelligence as malleable as opposed to fixed—enhances challenge-seeking, interest in learning, effort investment, use of effective strategies, achievement outcomes, and even how the brain functions. They discuss converging evidence for the malleability of intelligence drawn from recent research in cognitive neuroscience that indicates greater brain plasticity and development resulting from learning than previously thought to exist, as shown by the impact of training on executive functions and fluid intelligence. Finally, they discuss how mindsets can be influenced and changed, and the practical implications of this research for educational policy and practice.