Post-traumatic stress disorder (PTSD) is common in patients with chronic pain, adversely affects chronic pain outcomes, and is associated with opioid use and adverse opioid outcomes. Social support is a robust predictor of PTSD incidence and course as well as chronic pain outcome. We determined whether the association between PTSD and persistent opioid use was modified by emotional support in a cohort of patients receiving opioids for noncancer pain. Eligible participants were ≥18 years and had completed a new period of prescription opioid use lasting 30 to 90 days. Bivariate associations between cohort characteristics and each key variable was assessed using χ 2 tests for categorical variables and t -tests for continuous variables. Interaction between PTSD and emotional support was assessed by a priori stratification on low vs high emotional support. Participants (n = 808) were 53.6 (SD ± 11.6) years of age, 69.8% female, 69.6% White, and 26.4% African American. Overall, 17.2% had probable PTSD. High emotional support was significantly ( P < 0.0001) more common among those without probable PTSD. Prescription opioid use at 6-month follow-up was significantly ( P = 0.0368) more common among patients with vs without probable PTSD. In fully adjusted models, PTSD was no longer associated with opioid use at 6-month follow-up among participants with high emotional support. Among those with lower emotional support, PTSD was significantly associated with opioid use at 6-month follow-up in unadjusted (odds ratio = 2.40; 95% confidence interval: 1.24-4.64) and adjusted models (odds ratio = 2.39; 95% confidence interval: 1.14-4.99). Results point to the hypothesis that improvement of emotional support in vulnerable patients with chronic pain and PTSD may help reduce sustained opioid use.