The study sought to understand the general trajectory of children's executive function, as well as whether there was heterogeneity among monolingual English-speaking and dual language learning children in their growth of executive function. In addition, the study examined whether monolingual English-speaking and dual language learning children demonstrated different developmental trajectories in their executive function development. Two executive function measures, the Peg Tapping and the Dimensional Change Card Sort Task, were used in the study. Findings of 122 children (Mean age = 3.68 years; 57% monolingual English speaking, 43% dual language learning) showed there was linear growth on children's executive function. Both monolingual English-speaking and dual language learning children varied significantly in their initial level of executive function and in their growth rate of executive function over time. In addition, monolingual English-speaking children demonstrated higher initial levels of executive function than dual language learners, while dual language learning children showed a faster rate of growth in executive function measured by the Peg Tapping test.