This study aimed to compare the clinical efficacy of unilateral laminotomy for bilateral decompression (ULBD) performed using unilateral endoscopy (UE) versus unilateral biportal endoscopy (UBE) in patients with lumbar spinal stenosis (LSS). Sixty LSS patients were randomly assigned to a UE-ULBD group or a UBE-ULBD group (30 cases each). Intraoperative blood loss, operative time, time to first ambulation, length of hospital stay, and intraoperative/postoperative complications were recorded. Low back and leg pain were assessed using the visual analog scale (VAS), and functional status was evaluated using the Oswestry Disability Index (ODI) prior to surgery and at 3 and 6 months postoperatively. Quality of life was measured by the Swiss Spinal Stenosis (SSS) questionnaire preoperatively and at 6 months post-surgery. Surgical outcomes were evaluated using the modified MacNab criteria. No differences were found between groups for intraoperative blood loss, operative time, time to first ambulation, length of hospital stay, or intraoperative/postoperative complication rates (P>0.05). Compared with preoperative values, both groups showed notable reductions in VAS and ODI scores at 3 and 6 months postoperatively (P 0.05). The modified MacNab excellent-to-good rates were 93.33% in the UBE-ULBD group and 90% in the UE-ULBD group, with no significant between-group difference (P>0.05). UE-ULBD and UBE-ULBD represent reliable minimally invasive options for the surgical management of LSS.