This study assessed the availability of school-based income-generating activities (IGAs) in public secondary schools in Kilimanjaro region, Tanzania. Guided by Resource Dependency Theory, the study adopted a convergent design under a mixed research approach for data collection and analysis. Probability and non-probability sampling techniques were employed to obtain 36 Heads of Schools (HOSs), 360 Teachers, 432 Students, and 6 District Education Officers. The quantitative data were analyzed descriptively (frequency and percentage) and inferential statistics using the ANOVA statistical test and presented in form of tables. Qualitative data were coded to translate the responses into specific categories and themes. The study found that, school shops as the most practiced school-based IGAs in public secondary schools. The study also revealed that cafeteria and crop cultivation were moderately practiced IGAs. Moreover, the study also depicted that animal keeping, poultry keeping, fish farming, vegetable gardening, tree nursery, hiring of school vehicle, and renting school facilities ranked as the least practiced IGAs. Through ANOVA test, the study found that there was no significant difference in the mean response of HOSs, teachers, and students on the availability of income-generating activities in public secondary schools in Kilimanjaro region. The study concluded that the public secondary schools do not practice IGAs such as animal keeping, poultry keeping, fish farming, vegetable garden, tree nursery, hiring of school vehicles and renting school facilities. This could be due to limited land space and inadequate motivation for benefits accrue from these projects. Therefore, the study recommends that District Education Officers, Heads of Schools, teachers, and parents, should make sure that all public secondary schools are fully engaged in school-based income-generating activities to supplement the school's financial requirements. The Ministry of Education, Science and Technology should develop a clear directive policy based on the establishment and expansion of IGAs in public secondary schools in Tanzania.