This study examined gender differences in children's domain-specific theories of intelligence. It was based on Dweck's theory that individuals view intelligence as either fixed (entity theory) or flexible (incremental theory). The hypothesis that the mathematics and verbal domains would differ most for older, brighter girls who are highly sex-typed was partially confirmed in that brighter girls endorsed incremental theory more strongly for the verbal than the math area. Incremental theory was generally endorsed more by girls than boys, by more sex-typed than less sex-typed children, and by brighter than more average children. Interactions indicated the sex difference was strongest among less sex-typed bright children, and sex-typing differences greatest among bright boys. Theory of intelligence had little predictive value for academic performance. It was suggested that future research explore whether greater domain variation may occur in children with average intelligence than was evident here for a sample of generally above-average intelligence.