Purpose: To assess the efficacy of a food service implementation intervention designed to increase provision of foods consistent with nutrition guidelines on child consumption of fruit, vegetables, breads/cereals, meat/alternatives, dairy, and diet quality in care. Design: Exploratory cluster randomized controlled trial. Setting: Twenty-five childcare centers in New South Wales, Australia. Sample: Three hundred ninety-five children aged 2 to 5 years. Intervention: Centers were randomized to the intervention or control group. Intervention development was guided by the Theoretical Domains Framework and included securing executive support, provision of group training, resources, audit and feedback, and one-on-one support. The intervention was delivered across six months and the study was conducted between March and December 2016. Measures: Child diet was assessed by educators using a validated questionnaire modified for completion in childcare center. Analysis: Data were analyzed in SAS using generalized linear mixed models adjusted for clustering. Results: Children in the intervention group consumed significantly higher number of serves of vegetables (0.4 serves; P < .001), wholegrain cereals (0.7 serves; P = .02), and meat/alternatives (0.5 serves; P < .001), and had higher diet quality scores (10.3; P < .001). Conclusions: A food service intervention targeting the provision of food significantly improved child dietary intake in care. Such findings are relevant to health promotion practitioners responsible for supporting improvements in child diet.