Recent advances in statistical techniques for longitudinal data analysis have provided increased capabilities for elucidating individual differences in trajectories of change in child behaviours and abilities. However, most techniques still assume that there is a single underlying distribution with respect to changes over time, about which children are normally distributed. If there are multiple subgroups of youth following distinct developmental trajectories with unique predictors, however, the results of these statistical techniques may provide an incomplete analysis of the data. A newer class of statistical techniques, latent growth mixture modelling, provides a robust framework for examining heterogeneity in patterns of development. This paper illustrates the use of latent growth mixture modelling for examining heterogeneity in developmental trajectories of adolescent antisocial behaviour. (Contains 2 figures and 2 tables.)