Introduction: This systematic review examines the effectiveness of interventions in family child care (FCC) on (1) children's dietary intake, physical activity levels and weight, and (2) FCC health-promoting environments, policies, and practices. Quasi-experimental studies measuring these outcomes were included. Methods: All available articles up to July 2023 were searched using MEDLINE, ERIC, CINAHL, Embase, Scopus, and A+ Education, and 15 interventions were included. Methodological quality was assessed with the Effective Public Health Practice Project Assessment tool. Results: Thirteen studies were weak, and 2 strong in quality. Four interventions included children's dietary intake as an outcome measure, 2 included physical activity, and 3 weight status. Twelve interventions assessed nutrition and 7 physical activity environmental outcomes. Discussion: Interventions in FCC improved children's dietary intake, but their impact on physical activity and weight status was inconclusive. Furthermore, positive impacts were observed in environmental outcomes related to nutrition, whereas research on physical activity environmental outcomes was limited. Implications for Research and Practice: Future research could replicate interventions to validate effectiveness and understand positive outcome mechanisms. Future interventions might use FCC stakeholders’ input, incorporate innovative physical activity components, enhance FCC providers' position as role models, involve parents, and target those groups that are at a high risk of being obese.