Changes in student self- and task evaluations, subjective valuation, and achievement behavior in mathematics and English over the 1st year of junior high form the basis of this study. The transition to junior high has been found to negatively affect students' self-concept and subjective valuation in mathematics and English, but previous research has not addressed changes in task evaluations and achievement behaviors. Gender and level of academic achievement effects are also relevant to the nature of changes in student attitudes. The participants (N =400) were from 3 coeducational Australian government schools in metropolitan Sydney of comparable socioeconomic status. When changes in perceptions occurred, they were negative, and gender differences favored boys in mathematics and girls in English. However, the nature and extent of change was dependent on school and level of achievement.