The present study explored the association between child internalising and externalising problems in schools and demographic factors (sex and age), school functioning (academic performance and adaptive functioning) and teacher-reported student-teacher relationship quality in a cross-sectional study using structural equation modelling. The study was conducted among a sample of Norwegian schoolchildren (n=825) in grades 1-7. The results showed among others that conflict in student-teacher relationships had the strongest association with teacher-reported child externalising and internalising problems. The school system and the teachers probably need to place more focus on how to support children with these kinds of mental health problems. (Contains 1 table and 1 figure.)