Purpose: Concomitant ankle injuries associated with tibial shaft fractures can affect postoperative ankle joint pain and various postoperative ankle complications. This study compared the clinical outcomes between surgical treatment and conservative treatment of concomitant ankle injuries associated with tibial shaft fractures. Materials and Methods: From January 2015 to June 2020, a retrospective study was conducted on 118 tibia shaft fractures at the orthopedics department of the hospital. Associated ankle injuries were analyzed using plain radiographs, computed tomography (CT), magnetic resonance imaging (MRI), and intraoperative stress exams. The clinical outcomes were compared using the pain visual analog scale (pain VAS), American Orthopaedic Foot and Ankle Society Ankle-Hindfoot score (AOFAS score), and Karlsson–Peterson ankle score (KP score). Results: Seventy-two (61.02%) of the 118 cases were diagnosed with associated ankle injuries. Fifty-six cases underwent surgery for the ankle injury, and 16 cases underwent conservative treatment. The clinical results (according to the pain VAS score, AOFAS score, the KP score) were 1.79±1.26, 94.48±4.03, and 94.57±3.60, respectively, in the surgical treatment group, and 3.00±1.03, 91.06±3.02, and 91.25±3.31, respectively, in the conservative treatment group. Conclusion Surgical treatment showed better clinical outcomes than conservative treatment in concomitant ankle injury in tibia fractures. Therefore, surgical treatment produces better clinical outcomes than conservative treatment in concomitant ankle injuries in tibia fractures. Hence to improve the clinical outcomes, more attention is needed on ankle joint injury in tibial shaft fractures for selecting suitable surgical treatments for those patients.