This study examines the impact of principal leadership practices on student academic outcomes in four Hong Kong primary schools. Given the increased accountability mechanisms confronting schools in Hong Kong, this study is based on the assumption that principal practices that respond directly to accountability policy or link to human resources development will be most influential. This does not necessarily contradict the assumption that principal leadership practices are generic and contextualised. This study will adopt a case study design. The data will be collected from 4 local schools with varied strategies, including online student math tests, and teacher questionnaire surveys. The student math test items will be selected from item banks of standardised tests. The questionnaires will be adapted from Walker and Ko’s (2011) and Leithwood and Jantzi’ s (2000) scales respectively, each covering extensively 7 dimensions with the number of items reduced to 33. The test scores will be aggregated and standardised, and used as student academic outcomes. The two questionnaires will be combined and used for the teacher survey. They will attempt to measure teachers’ perceptions of principal leadership practices and conditions in the schools. The individual responses of the participants will be aggregated to the person level and school level, and then subjected to descriptive, comparative, and inferential statistical analyses. Factors from both principal leadership practices and school conditions that synergistically contribute to student achievement will be indentified and verified, and effects specified. Given the limited number of schools in the sample, findings at the teacher and student levels will be triangulated and discussed as rich descriptions of cases. It is hoped that it will inform practitioners and researchers the interrelatedness between principal leadership practices, school conditions, and student achievement. The findings may also generate some indicative findings