Pre-print, Working paper: When potential beneficiaries share knowledge and attitudes about a policy intervention, that can influence their decisions to participate and, in turn, change the effectiveness of both the policy and its evaluation. This matters notably in integrated social policies with several components. We examine neighborhood effects on the take-up of the schooling subsidy component of the Progresa-Oportunidades program in Mexico. We exploit random variations in the local densities of program beneficiaries generated by the randomized evaluation. Higher program densities in areas of 5 km radius increase the take-up of scholarships and enrollment at the junior-secondary level. These neighborhood effects exclusively operate on households receiving another component of the program, and do not carry over larger distances. While several tests reject heterogeneities in impacts due to spatial variations in implementation, we find suggestive evidence that neighborhood effects stem partly from the sharing of information about the program among eligible households.