An important aspect of executive functioning is the ability to flexibly switch between behavioral rules. This study explored how considering the multidimensionality of objects affects behavioral rule switching in 3-year-old children. In Study 1 (N = 40), children who participated in a brief game separating and aggregating an object's dimensions (i.e., color and shape) showed improved performance on the Dimensional Change Card Sort (DCCS), a measure of behavioral rule switching, relative to controls. In Study 2 (N = 80) DCCS performance improved even when the initial practice involved a different dimension (pattern and shape). Thus, practice thinking about multidimensionality can affect 3-year-olds' DCCS performance and therefore may play an important role in the development of flexible thinking.