Data from a randomly selected sample of 840 Ontario students were used to examine factors that affect self-rated physical health. Analyses focused on demographics, family structure, family financial situation, child-parent relationship, school achievement, self-esteem, alcohol, tobacco and cannabis use as factors which directly and indirectly influence self-rated health. Specifically, higher income, good child-parent relationship, higher interest and achievement in school, high self-esteem, not smoking, and being male were all positively and directly associated with higher self-ratings of health. Family structure was mediated by income, and school achievement and child-parent relationship were mediated by tobacco use and self-esteem. Our analyses suggest that student perceptions of physical health are affected by demographic, economic, social, psychological and competency factors. (C) 1998 The Association for Professionals in Services for Adolescents.