Access to affordable daycare might improve population mental health. However, evidence is sparse and restricted to middle- and high-income country settings. We conducted a cluster-randomized controlled trial in one low-income setting, rural Rajasthan, India. Communities lacking daycare facilities were identified (n = 160) and randomly selected for assistance in setting up a community-based daycare program (n = 80) or not (n = 80). Women eligible for the daycare program living in these communities completed structured interviews before the intervention (participation rate = 89%) and approximately one year after rollout of the intervention (participation rate = 96%), resulting in a final analytic sample of 3041. Mental distress was measured with the Hindi version of the 12-item General Health Questionnaire (score range: 0-12). We modeled the relation between access to daycare and number of mental distress symptoms (GHQ-12 score) with negative binomial regression using an intention-to-treat approach, which groups women according to if they lived in communities randomized to affordable daycare. We also evaluated the effect of access to daycare on secondary outcomes that may be related to mental distress, including women’s work burden, agency, and intimate partner violence (IPV). We found that access to daycare resulted in modest reductions in symptoms of mental distress (mean difference = 0.21, 95% CI: -0.43, 0.02). We found some evidence that daycare reduced IPV, but virtually no change in women’s work burden or agency. Our results provide some indication that access to affordable daycare might be one policy lever to improve population mental health.