This study examined the influence of urban social policy interventions on the welfare and reintegration outcomes of street children in Kampala Central Division, Uganda's most densely populated and commercially active administrative division. Drawing on a mixed-methods cross-sectional study involving 214 respondents comprising current street children aged 8–17, recently reintegrated former street children, social workers, KCCA officers, and NGO programme staff -the study assessed how child protection policy implementation, rehabilitation programme quality, and family reintegration support services influenced street children's welfare outcomes including school enrolment, health access, and sustainable reintegration success. Descriptive statistics revealed significant policy implementation gaps across all dimensions (means 2.87–3.24). Pearson correlation confirmed significant positive relationships between all three policy dimensions and child welfare outcomes (r = 0.561–0.691, p < .001). Multiple regression demonstrated that the three dimensions explained 58.4% of variance in child welfare outcomes (R² = 0.584, F = 27.83, p < .001). SEM analysis confirmed child protection policy implementation as the strongest total effect predictor (total β = 0.463), with rehabilitation programme quality partially mediating policy implementation effects. The study called for a comprehensive Street Children Elimination Strategy for Kampala, integrated multi-agency coordination, and sustained funding for prevention, rehabilitation, and reintegration programming.