We evaluated the effect of a weight gain prevention intervention (Shape Program) on depression among socioeconomically disadvantaged overweight and obese Black women.Between 2009 and 2012, we conducted a randomized trial comparing a 12-month electronic health-based weight gain prevention intervention to usual primary care at 5 central North Carolina community health centers. We assessed depression with the Patient Health Questionnaire (PHQ-8). We analyzed change in depression score from baseline to 12- and 18-month follow-up across groups with mixed models. We used generalized estimating equation models to analyze group differences in the proportion above the clinical threshold for depression (PHQ-8 score ≥ 10).At baseline, 20% of participants reported depression. Twelve-month change in depression scores was larger for intervention participants (mean difference = -1.85; 95% confidence interval = -3.08, -0.61; P = .004). There was a significant reduction in the proportion of intervention participants with depression at 12 months with no change in the usual-care group (11% vs 19%; P = .035). All effects persisted after we controlled for weight change and medication use. We saw similar findings at 18 months.The Shape Program, which includes no mention of mood, improved depression among socioeconomically disadvantaged Black women.