Research Findings: This study evaluated the impacts of the Summer Preschools Program on 5-to-6-year-old Syrian refugee and local children from vulnerable communities of Turkey. Developed as a community-based contextually sensitive early intervention model, the program aimed to promote developmental well-being and school readiness of children from forced displacement and abject poverty backgrounds by supporting cognitive, language, and socioemotional development prior to primary school. A skill-based preschool education curriculum was implemented with 2620 children for 10 weeks at 140 classrooms in Southeastern Anatolia region across the war-torn border zone with Northern Syria. The study included 711 children in quasi-experimental design and pursued a multi-measure evaluation approach in seven early development domains. ANCOVA analyses revealed that after controlling for pretest scores, the intervention group scored significantly higher than the control group on posttest measures of preliteracy and prenumeracy, receptive and expressive language, and emotion-regulation skills. Additionally, there was a significant increase in social competence skills and decrease in internalizing/externalizing behavior problems. Intervention resulted in substantial improvements with mostly medium-to-large effect size. Overall, results suggest the effectiveness of the Summer Preschools as a compensation intervention strategy that can foster developmental well-being, school readiness, and resilience of children exposed to early life adversities. Practice or Policy: With its conceptual framework, intervention content, and implementation structure, the Summer Preschools model can inform support services and education policies of countries grappling with refugee influx.