This project was concerned with the relationship between children's explanatory style (optimism vs. pessimism) and achievement in mathematics indexed by the Progressive Achievement Test. One hundred and 45 children from grades 4, 6 and 7 (aged 8 to 12 years) participated as subjects. The Children's Attributional Styles Questionnaire (CASQ) correlated significantly (r=.34) with current achievement, and scores on the negative subscale of the CASQ correlated with achievement data collected 2 and 3 years previously. On a further questionnaire concerned with motives for learning, optimistic children endorsed task-orientation goals whereas, ego-orientation goals were endorsed by both optimistic and pessimistic children. Significant sex differences were found on the CASQ, with a greater number of boys displaying a relatively depressogenic pattern.