Chronic low back pain is common, disabling, and often inadequately controlled with current pharmacologic options, underscoring the need for safer non-opioid treatments. Dronabinol, a synthetic formulation of Δ9-tetrahydrocannabinol, has analgesic potential but has not been rigorously evaluated for chronic low back pain. This article describes a phase IIa, single-site, randomized, double-blind, placebo-controlled, parallel-group trial in Veterans with chronic low back pain. Seventy-five participants will be randomized 2:1 to oral dronabinol or matching placebo for 8 weeks following a screening period of up to 4 weeks. The primary objective is to evaluate safety and tolerability. Primary outcomes include treatment-emergent adverse events, serious adverse events, laboratory findings, vital signs, and electrocardiogram results. Secondary outcomes are exploratory and include pain intensity, physical functioning, emotional functioning, global improvement, analgesic use, and medication adherence. This study is designed to generate safety data and preliminary estimates of variance and effect size to inform a future confirmatory trial; it is not powered to test efficacy hypotheses.Clinical trial registration: http://www.clinicaltrials.gov identifier is NCT06454669.