Restrictions in ankle dorsiflexion range of motion (ROM) have been associated with decreased posterior talar glide in individuals with an acute lateral ankle sprain. Talocrural joint mobilizations may be used to restore joint arthrokinematics. Our purpose was to examine the effects of a single bout of anterior to posterior (AP) talocrural joint mobilization on self-reported function, dorsiflexion ROM, and posterior talar translation in individuals with an acute lateral ankle sprain. This single-blinded, randomized controlled trial utilized 17 volunteers (nine treatment and eight control) with an acute lateral ankle sprain (grade I/II) who were immobilized for a period of 1-7 days. The treatment group received a single 30-second bout of grade III AP talocrural joint mobilization the day their immobilization device was removed, while the control group did not receive any intervention. Active dorsiflexion ROM and posterior talar translation were assessed before, immediately after, and 24 hours after receipt of the treatment or control interventions. Self-reported function and pain were assessed before and 24 hours after the receipt of the treatment or control interventions using the foot and ankle disability index. Collectively all groups demonstrated improved dorsiflexion ROM and self-reported function. There was a significant decrease in pain perception at 24-hour follow-up for the treatment group. A single bout of AP talocrural joint mobilizations may not have an immediate effect on ankle dorsiflexion ROM, posterior talar translation, or self-reported function; however, they may have an immediate effect on pain perception in individuals with an acute lateral ankle sprain.