Methadone maintenance treatment (MMT) is effective for managing opioid use disorder, but adverse effects mean that optimal therapy occurs with the lowest dose that controls opioid craving. To assess the efficacy of acupuncture versus sham acupuncture on methadone dose reduction. Multicenter, 2-group, randomized, sham-controlled trial. (Chinese Clinical Trial Registry: ChiCTR2200058123). 6 MMT clinics in China. Adults aged 65 years or younger with opioid use disorder who attended clinic daily and had been using MMT for at least 6 weeks. Acupuncture or sham acupuncture 3 times a week for 8 weeks. The 2 primary outcomes were the proportion of participants who achieved a reduction in methadone dose of 20% or more compared with baseline and opioid craving, which was measured by the change from baseline on a 100-mm visual analogue scale (VAS). Of 118 eligible participants, 60 were randomly assigned to acupuncture and 58 were randomly assigned to sham acupuncture (2 did not receive acupuncture). At week 8, more patients reduced their methadone dose 20% or more with acupuncture than with sham acupuncture (37 [62%] vs. 16 [29%]; risk difference, 32% [97.5% CI, 13% to 52%]; P < 0.001). In addition, acupuncture was more effective in decreasing opioid craving than sham acupuncture with a mean difference of -11.7 mm VAS (CI, -18.7 to -4.8 mm; P < 0.001). No serious adverse events occurred. There were no notable differences between study groups when participants were asked which type of acupuncture they received. Fixed acupuncture protocol limited personalization and only 12 weeks of follow-up after stopping acupuncture. Eight weeks of acupuncture were superior to sham acupuncture in reducing methadone dose and decreasing opioid craving. National Natural Science Foundation of China.