Reading comprehension ability relies heavily on executive function skills which can be improved with selective interventions. Cognitively engaging physical activity promotes executive function acquisition and may be helpful to improving reading ability. However, unfamiliar and potentially stressful interventions may be counterproductive to these improvements. This study examines the effect of tennis exercise on executive function in children (N = 17) who had no experience in racquet sports. In a counterbalanced and randomized crossover trial, children completed the d2 Test of Attention before and after 15 minutes of tennis activity and, on a different day, a time-matched sedentary control condition. Repeated measures ANOVAs were used to assess the main effects of, and interaction between, condition and time on processing speed, concentration performance, and error percentage. The improvement in executive function measures following tennis were small (0.027 < [eta][superscript 2] < 0.049) and non-significant (p > 0.05 in all cases) compared to the control condition, in contrast to findings of similar studies. The cognitive challenge of, and lack of familiarity with, the tennis exercise may have offset the improvement in executive function that is typically observed following moderate-intensity exercise. Such exercise attributes should be considered by practitioners when selecting appropriate interventions.