A longitudinal modeling approach was utilized to determine the existence of latent classes with regard to academic intrinsic motivation and the points of stability and transition of individuals between and within classes. A special type of latent Markov Chain model using "Mplus" was fit to data from the Fullerton Longitudinal Study, with academic intrinsic motivation measured from ages 9 through 17. Model fit using the Bayesian Information Criterion index was examined. The best fit involved a 3-class model, with classes designated as motivationally gifted, intermediate, and at-risk. Transitions between classes occurred mainly during childhood, whereas stability ensued by age 13. Methodological contributions are discussed, as well as theory and applications of the findings with regard to academic intrinsic motivation. (Contains 1 figure, 5 tables, and 1 note.)