Students' self-concept and effort in schoolwork are known to have significant influences on essential academic outcomes, but self-concept and effort may decline as students grow up. Students from 16 schools in Sydney (N = 2200) were asked to rate on two self-concept components (competency and affect) and effort in schoolwork. Based on measures established in confirmatory factor analysis, a 5 (grade: 3rd, 5th, 7th, 9th, 11th) x 2 (gender: boys, girls) x 3 (measure: competency, affect, effort) repeated-measures ANOVA found that: (a) for all variables, scores were lower for higher grade levels; (b) boys were lower in affect and effort; (c) particularly for effort, gender differences favouring girls in primary became negligible in higher secondary; and (d) differences between primary and secondary tended to be greater for girls. Educators and curriculum designers need to consider the self-concept and effort of boys in the primary and girls in the secondary. (Contains 3 figures and 2 tables.)