There is disagreement among researchers as to whether creativity is a unidimensional or multidimensional trait. Much of the debate centers around the most widely used measure of creativity, the Torrance Tests of Creative Thinking (TTCT). This study used data from 1,000 kindergartners (ages 5-7), 1,000 third graders (ages 7-11) and 1,000 sixth graders (ages 10-13). Confirmatory factor analyses were conducted for both the two-factor model and one-factor model to determine which fit the data better. Measurement invariance across genders and grade levels was assessed using multiple group analyses in which sets of parameters were freed sequentially in a series of hierarchically nested models. The findings indicate that the structure of TTCT scores is consistent with a two-factor theory. Also, the results of the multiple group analyses indicate that model parameters for gender groups are more invariant than for grade levels in determining the fit of the model. (Contains 6 tables.)