Background: It is unclear what effects a conditional cash transfer (CCT) program would have on child anthropometry, language development, or school achievement in the context of the nutrition transition experienced bymany low- and middle-income countries. Objective: We estimated the association of participation in Peru's Juntos CCT with anthropometry, language development, and school achievement among children aged 7-8 y. Methods: We used data from the Young Lives Study of a cohort born between 2001 and 2002. We estimated associations of the Juntos program with height-for-age z score (HAZ), body mass index-for-age z score (BAZ), stunting, and overweight at age 7-8 y separately for children participating in the program for <2 y (n = 169) and children participating for <2 y (n = 188). We then estimated associationswith receptive vocabulary and grade achievementamong childrenwho had been assessed at age 4-6 y before enrollment in Juntos (n = 243).We identified control subjects using propensity score matching and conducted difference-in-differences comparisons. Results: Juntos participation was associated with increases in HAZ among boys participating for 2 y [average effect of treatment among the treated (ATT): 0.43; 95%CI: 0.09, 0.77; P = 0.01] and for boys participating for <2 y (ATT: 0.52; 95%CI: 0.23, 0.80; P < 0.01). Among girls participating in the program for ≥2 y, BAZ declined (ATT: -0.60; 95%CI: -1.00, -0.21; P < 0.01) as did the prevalence of overweight (ATT: -22.0 percentage points; 95% CI: -42.5, -2.7 percentage points; P = 0.03). We observed no significant associations of Juntos participation with receptive vocabulary or grade attainment. Conclusions: CCT program participation in Peru was associated with better linear growth among boys and decreased BAZ among girls, highlighting that a large-scale poverty-alleviation intervention may influence anthropometric outcomes in the context of the nutrition transition.