This study examined the effects of perceived control on engagement and achievement in mathematics. Year 10 students were asked to indicate their level of agreement with statements about strategies for achieving success and avoiding failure in mathematics and to what extent they felt they personally had the capacity to employ these strategies. Students were also surveyed about the level of control they had over success and failure, and the level of cognitive and emotional engagement that they felt in mathematics. Their teachers were asked separately for their perceptions of each student's level of cognitive and emotional engagement. Engagement, confidence and achievement were found to be promoted by high control beliefs, and by high strategy and capacity beliefs in ability. In contrast, engagement was found to be undermined by low capacity beliefs about ability, powerful others and luck.