Exploratory learning before instruction can benefit understanding, but can also be challenging. Individual differences in response to challenge, such as achievement motivation, may therefore moderate the benefits of exploratory learning. Higher mastery orientation generally leads to increased effort in response to challenge, whereas higher performance orientation leads to withdrawal. Children (2nd-4th grade; N=159) were given mathematical equivalence problems to solve as either an exploratory learning activity (before instruction) or as practice (after instruction). Higher mastery orientation was associated with improved learning from exploration. In contrast, performance orientation did not lead to learning improvements—and sometimes even hurt learning. Higher mastery orientation was also associated with more sophisticated problem-solving strategies during exploration. Although exploratory activities have the potential to advance strategy selection and subsequent learning, achievement motivation may boost or hinder these benefits.