Diabetic retinopathy leads to vision-threatening complications, such as proliferative diabetic retinopathy and tractional retinal detachment (TRD) and is a major global health concern. Despite advancements in vitrectomy techniques, challenges exist in managing postoperative complications and long-term visual acuity. This study aimed to evaluate postoperative outcomes of 27-gauge pars plana vitrectomy (27g PPV) for diabetic TRD and identify associated risk factors. Retrospective study. This study included 94 eyes of 74 patients who underwent 27g PPV for diabetic TRD between July 2017 and September 2022 at Juntendo University Urayasu Hospital, Japan. Patient demographics, preoperative characteristics, intraoperative details, and postoperative outcomes were examined. Statistical analyses were performed to identify factors influencing postoperative visual acuity. Mean follow-up duration was 23.1 ± 14.6 months. Postoperatively, visual acuity (LogMAR) improved significantly from 1.34 ± 0.82 to 0.65 ± 0.79 (P < 0.0001). Postoperative complications included persistent vitreous hemorrhage (15%) and neovascular glaucoma (4%). Final retinal reattachment rate was 97%. Preoperatively, macular detachment (P < 0.0001) and Grade IV TRD (P < 0.0001) severity were significantly associated with poor final best corrected visual acuity (P < 0.0001). Preoperative macular detachment (P < 0.0001), Grade IV TRD (P < 0.0001), intraoperative iatrogenic breaks (P = 0.031), and postoperative neovascular glaucoma (P < 0.0001) were identified as significant predictors of poor postoperative visual outcomes through multivariate analysis. This study highlights the efficacy of 27g PPV in improving visual acuity in patients with diabetic TRD. Despite favorable outcomes, attention to preoperative risk factors and meticulous surgical techniques remain crucial for optimizing long-term visual prognosis in these patients.