Recent education reform in Hong Kong has been largely based on the premise that the motivation of many secondary school students is lacking. However, the empirical base underlying this premise is weak. This study explored the development of students' academic motivation in secondary schools. It improved on the previous Hong Kong research in terms of the representativeness of sample and depth of enquiry. Mastery, performance-approach, social status, social approval, social affiliation, social concern, extrinsic, and prospects goals were examined. They were measured by a Chinese version of Inventory of School Motivation Revised. The participants were initially 354 S1 and 343 S3 students from three secondary schools with ability bands ranging from 1 to 3. A year later, 176 S6 students of the schools were also included in the sample. The one-year longitudinal changes (for the then S2 and S4 students) and grade-level differences (between the S2, S4, and S6 students) in goal orientations were examined. Multiple regression analysis was used to explore the relative strength of the goals in predicting a range of educational outcomes: general motivation, academic self-esteem, academic achievement, and use of surface, deep, and achieving learning strategies. The development of these educational outcomes was also examined. Also, 36 participants attended individual interviews. These explored their purposes of schooling, conceptions of ability, and attribution of school performance. Overall, the longitudinal and cross-sectional studies showed that the goal orientations and educational outcomes were fairly stable with medium to high mean scores. This finding is not in line with those of U.S. studies which indicate a general decline in students’ motivation during middle and high school years. Relatively speaking, there is a lack of non-Western research on the development of school motivation. Policy-makers in Hong Kong or elsewhere should not assume U.S. research applies in their context