Objective To compare the clinical efficacy of unilateral biportal endoscopic transforaminal lumbar interbody fusion (UBE-TLIF) and minimally invasive transforaminal lumbar interbody fusion (MIS-TLIF) in the treatment of elderly patients with single-segment degenerative lumbar spondylolisthesis (DLS). Methods Clinical data of 94 elderly patients with single-segment DLS were retrospectively analyzed and divided into UBE-TLIF group (n=45) and MIS-TLIF group (n=49) according to surgical approach. The operative duration and intraoperative blood loss were compared between the two groups. The pain visual analogue scale (VAS) and Oswestry disability index (ODI) scores were assessed preoperatively and at 1 week, 1 month, 3 months and 1 year postoperatively. The MOS 36-item short-form health survey (SF-36) was used to evaluate the quality of life of the two groups preoperatively and at 1 year postoperatively. Complications including incision infection, dural tear, increased intracranial pressure, epidural hematoma and residual neurological symptoms were recorded. At 3 months postoperatively, the reduction rate of lumbar spondylolisthesis and interbody fusion were compared between the two groups. Results The UBE-TLIF group had a longer operative duration but less intraoperative blood loss than the MIS-TLIF group (P<0.05). At 1 week postoperatively, the pain VAS and ODI scores were lower in the UBE-TLIF group than in the MIS-TLIF group (P<0.05). At 1 month, 3 months and 1 year postoperatively, the pain VAS and ODI scores in both groups were significantly lower than the preoperative levels (P<0.05). SF-36 scores increased significantly in both groups at 1 year postoperatively (P<0.05), with no statistically significant intergroup difference (P>0.05). No statistically significant differences were found in overall complication rate, spondylolisthesis reduction rate or interbody fusion between the two groups (P>0.05). Conclusion Both UBE-TLIF and MIS-TLIF yield comparable therapeutic efficacy for elderly patients with single-segment DLS, as evidenced by significant pain relief, improved lumbar function and enhanced quality of life. Nevertheless, UBE-TLIF results in less intraoperative blood loss and facilitates earlier postoperative recovery. Therefore, individualized surgical selection should be performed according to patients' clinical characteristics.