Many children in Zambia miss measles vaccination through routine immunization, while supplementary immunization activities (SIAs) targeting children under five may not reach older under-vaccinated children. School-based vaccination screening and catch-up (SVS) is a recommended strategy to identify and vaccinate these children, but evidence on its implementation and cost in sub-Saharan Africa is limited. We estimated the cost of an SVS pilot for measles vaccination in Zambia to inform implementation and potential scale-up.,We conducted an ingredients-based costing from the Government of Zambia perspective of an SVS pilot in 20 urban schools in Lusaka and rural schools in Masaiti. Costs were estimated under three scenarios: base case (full pilot costs); post-introduction (excluding start-up and technical support); and budgeting (assuming full program integration and excluding start-up, technical support, and Ministry of Health and Education staff costs). One-way and probabilistic sensitivity analyses were conducted. Costs are reported in 2024 USD and Zambian kwacha (ZMW).,Among 3,351 children screened, 215 were identified as measles-rubella (MR) zero-dose and 211 were vaccinated. Total implementation cost was USD 75,886 (ZMW 2,111,157) in the base case. By input, personnel accounted for 70.6% of costs. By SVS activity, coordination and training accounted for 46.8% and 34.0% of total costs, respectively. Costs decreased by 28.3% in the post-introduction and 42.3% in the budgeting scenario. Cost per child screened ranged from USD 13.05–22.65, and per MR zero-dose child vaccinated from USD 208.29–360.70. Coordination time was the most influential parameter.,While costs per child are relatively high, SVS is a targeted strategy that can be used to reach older children who remain unreached by routine immunization programs and SIAs. Efficiency could improve through streamlined documentation, integration with school health activities, and reduced coordination and personnel requirements. Further research should assess its comparative value and cost-effectiveness against other approaches.