The present study used a family systems approach to examine harsh parenting, maternal depressed affect, and marital quality in relation to children's externalising behaviour problems in a sample of 158 Hong Kong primary school children. At two time points, peers and teachers provided ratings of children's externalising behaviours, and mothers completed questionnaires assessing depressed affect, marital quality, and harsh parenting. Path analyses showed that maternal depressed affect had both direct effects on child externalising and indirect effects through harsh parenting. The effect of marital quality on child externalising was not direct but was mediated through harsh parenting. These findings reflect family processes that have similarities with those found in Western samples as well as differences in terms of how Hong Kong Chinese culture may facilitate and inhibit these processes. (Contains 1 table and 2 figures.)