BACKGROUND Gastrocnemius stretching exercises often are prescribed as part of the treatment program for patients with overuse injuries associated with limited ankle dorsiflexion. However, little is known about how the position of the subtalar joint during gastrocnemius stretching affects ankle dorsiflexion range of motion (ROM). OBJECTIVE To determine the effect of subtalar joint position during gastrocnemius stretching on ankle dorsiflexion ROM. METHODS This study was a 3-way mixed-model design. The 3 factors were subtalar joint position (supinated, pronated), lower extremity (experimental, control), and time (pretest, posttest). Lower extremity and time were the repeated measures. METHODS University research laboratory. METHODS Thirty-three healthy volunteers (29 women, 4 men). METHODS Participants performed a gastrocnemius stretching exercise 2 times daily for 3 weeks with the subtalar joint of the randomly assigned experimental side (dominant or nondominant) in the randomly assigned position (supination or pronation). The contralateral lower extremity served as the control. METHODS Before and after the 3-week gastrocnemius stretching program, we used goniometers to measure ankle dorsiflexion ROM in weight-bearing and non-weight-bearing positions with the subtalar joint positioned in anatomic 0 degrees . RESULTS Ankle dorsiflexion ROM measured in weight-bearing and non-weight-bearing positions increased after the gastrocnemius stretching program (P = .034 and .003, respectively), but the increase in ROM did not differ based on subtalar joint position (P = .775 and .831, respectively). CONCLUSIONS Subtalar joint position did not appear to influence gains in ankle dorsiflexion ROM after a gastrocnemius stretching program in healthy volunteers.