Unilateral biportal endoscopy (UBE) can be used to treat common lumbar pathologies, such as synovial facet cysts, foraminal disc herniations, and foraminal stenosis via a contralateral sublaminar approach. Due to the ultra-minimally invasive technique, UBE can reduce damage to anatomical structures, thereby reducing postoperative pain and allowing faster recovery. The patient is placed prone on a Wilson frame or bolsters. Fluoroscopy is used to identify the midline and medial pedicle line in the anterior-posterior projection. Spinal needles can aid to identifying portals’ trajectory in the lateral fluoroscopic projection. The procedure is performed via 2 separate portal incisions. The endoscope is introduced through the viewing portal and the surgical instruments through the working portal. Soft tissue dissector is used to create a working area over the spinous process-lamina junction. Bony shaving and drilling start at the target area and continue medially underneath the base of the spinous process until the midline and contralateral ligamentum flavum are identified. Contralateral ligamentum flavum is excised, exposing thecontralateral thecal sac, traversing nerve root, and lateral recess. The contralateral disc space, annulus, and superior articulating process are then identified and the offending pathology can be addressed under direct visualization. Meticulous hemostasis and close attention to outflow should be maintained to reduce the risk of complications. The steps of this procedure closely resemble those of traditional microscopic “over-the-top” techniques, including the surgical instruments used through the working portal. In this video, authors present the surgical technique of the contralateral sublaminar approach in the lumbar spine with UBE.