This study explored the association between teacher-reported student-teacher relationship quality (closeness and conflict) and demographic factors, school functioning and child mental health in a cross-sectional study. The study was conducted among a national sample of Norwegian school children (N?=?825) in grades 1 to 7. Bivariate analyses and standard multiple regression analysis were conducted. Conflict in student-teacher relationships correlated highly with child mental health factors and in particular, problems of externalization. For closeness in student-teacher relationships, demographic factors accounted for the largest proportion of variance. Our findings suggest that different strategies may be needed to promote closeness and reduce conflict in student-teacher relationships. (Contains 4 tables.)