The aim of this study was to explore the effects of preschooler PA in two separate environments (indoor/outdoor) on measures of executive functions in preschoolers. Eighteen preschool-age (3–5 years) children were recruited for the study. Participants of the study wore an accelerometer for 30 min during indoor classroom-based activities and 30 min during outdoor PA. Pre and post inhibitory control and simple reaction time assessments were completed for each condition, for a total of four assessments for each participant. One assessment of the inhibitory control task (Arrows) resulted in a significant interaction of time x condition, F(1,16) = 3.42, p = .08, partial η2 = 0.18. These results indicate that performance improved in response to outdoor PA, but declined in response to indoor classroom activities. This research suggests that outdoor PA may result in cognitive benefits that are not observed following indoor classroom activities on one assessment of inhibitory control. Providing more scheduled time for PA for preschoolers is recommended for these reasons. (author abstract)