This study applied piecewise latent growth modeling to longitudinal survey data from 2 different samples of adolescents (N=1,002 and N=1,206) to examine the hypothesis that development of sensation seeking in middle school would predict development of substance use (cigarettes, alcohol, and marijuana) in middle school and high school. Results showed that sensation seeking had strong predictive value for both concurrent and distal marijuana and alcohol use in both samples; however, initial level of sensation seeking predicted initial level of cigarette use during high school in 1 sample only. White participants scored consistently higher on both initial level and rate of increase in sensation seeking than did participants of other ethnicities. Advantages of this methodology are discussed in the context of substance use research.