BACKGROUND Written local wellness policies (LWPs) are mandated in school systems to enhance opportunities for healthy eating/activity. LWP effectiveness relies on school‐level implementation. We examined factors associated with school‐level LWP implementation. Hypothesized associations included system support for school‐level implementation and having a school‐level wellness team/school health council (SHC), with stronger associations among schools without disparity enrollment (majority African‐American/Hispanic or low‐income students). METHODS Online surveys were administered: 24 systems (support), 1349 schools (LWP implementation, perceived system support, SHC). The state provided school demographics. Analyses included multilevel multinomial logistic regression. RESULTS Response rates were 100% (systems)/55.2% (schools). Among schools, 44.0% had SHCs, 22.6% majority (≥75%) African‐American/Hispanic students, and 25.5% majority (≥75%) low‐income (receiving free/reduced‐price meals). LWP implementation (17‐items) categorized as none = 36.3%, low (1–5 items) = 36.3%, high (6+ items) = 27.4%. In adjusted models, greater likelihood of LWP implementation was observed among schools with perceived system support (high versus none relative risk ratio, RRR = 1.63, CI: 1.49, 1.78; low versus none RRR = 1.26, CI: 1.18, 1.36) and SHCs (high versus none RRR = 6.8, CI: 4.07, 11.37; low versus none RRR = 2.24, CI: 1.48, 3.39). Disparity enrollment did not moderate associations (p > .05). CONCLUSIONS Schools with perceived system support and SHCs had greater likelihood of LWP implementation, with no moderating effect of disparity enrollment. SHCs/support may overcome LWP implementation obstacles related to disparities.