This study was designed to investigate the social characteristics associated with the height of primary schoolchildren aged from 5 to 11. Data were analysed for 8491 representative sample children measured in England and Scotland in 1987 and 1988 and 3203 inner city children measured in England in 1987. Height was negatively associated with social class but the association was not significant after allowing for biological variables. A negative gradient of height with size of sibship was evident in white children but was less so in Afro-Caribbean and Asian children. The individual associations of 11 different environmental characteristics were examined after allowing for biological factors and size of sibship. Consistent associations with height included a negative gradient of height with increasing latitude and an association of taller stature with increasing maternal age. A social class gradient in height is accounted for by associations with biological factors, particularly the parental heights; environmental attributes are weakly associated with height after allowing for biological factors.