This paper examines the ways in which children's beliefs about their abilities influence their academic achievement. These beliefs interact with the demands of different tasks or learning situations. Research is described which deals with children's causal attributions for their academic success or failure and with children's definitions of intelligence. Research suggests that the impact of children's beliefs varies as a function of the particular learning situation. In addition, children's beliefs about their abilities are not simply mirror reflections of their actual abilities or previous performances. Several studies are described which examine children's effort, performance, and causal attributions of ability and intelligence in a variety of situations. Three sex differences emerged: (1) females exhibited less confidence in their ability to succeed in challenging tasks; (2) females exhibited less confidence in social studies and science tasks than in reading, language arts, and mathematics tasks which involve more feedback; and (3) females were likely to have decreasing mathematics confidence as they become older. Since some childhood beliefs are not adaptive, it is recommended that ways to encourage facilitative beliefs be found. (GDC)