Background and Objectives: Repetitive ankle sprains lead to mechanical instability of the ankle. Patients with chronic ankle instability may experience decreased muscle strength and limited postural control. This study investigated the effects of a hip-strengthening exercise program on muscle strength, balance, and function in patients with chronic ankle instability. Materials and Methods: A total of 30 patients participated in the study and were randomly assigned to the two groups. Among the 30 participants, 14 were assigned to the hip joint-strengthening exercise group and 16 to the control group. The experimental group underwent a hip-strengthening exercise program and received training for 40 min per session twice a week for four weeks. The control group received the same frequency, duration, and number of sessions. Measurements were performed before and after the training period to assess changes in hip strength, balance, and function. Results: In the within-group and between-group comparisons, both groups showed significant differences in hip joint strength, static balance, dynamic balance, and function (FAAM; foot and ankle ability measures) (p < 0.05). Statistically significant differences were observed in the time × group interaction effects among the hip abductors and external rotation in hip joint strength, path length in static balance, posterolateral and posteromedial in dynamic balance, and FAAM-ADL and FAAM-SPORT functions (p < 0.05). Conclusions: Accordingly, this study confirmed that hip joint-strengthening exercises have a positive effect on the strength, balance, and function of patients with chronic ankle instability, and we believe that hip joint-strengthening exercises will be recommended as an effective intervention method for patients suffering from chronic ankle instability.