Although donor funding has helped to boost the education sector, questions have arisen regarding the sustainability of donor-funded schools. The objective of this study was to investigate the influence of management skills on the sustainability of donor-funded schools in Kiambaa Constituency, Kiambu County, Kenya. Resource Dependency Theory and Agency Theory guided the study. The study employed the descriptive survey design and targeted the population of 122 stakeholders of the White Cottage Schools and the Bridge International Academies comprising 100 parents, 2 managers, and 20 teachers. The systematic sampling method was used to select a sample of 50 parents and 10 teachers while both managers were included in the study sample making a sample size of 62 respondents. Quantitative data were collected from parents using questionnaires, while qualitative data was obtained from the teachers and managers using interview guides. Quantitative data were analyzed using descriptive statistics and the chi-square test, while qualitative data were analyzed using the thematic content analysis technique. Results showed that more than half of the parents believe that their children’s schools would not operate optimally without donor funds. Results further showed that the sustainability of donor-funded primary schools was significantly associated with managerial skills, including creativity, flexibility, and networking. The study concluded that managerial skills are a significant determinant of donor-funded schools' sustainability. The study recommends that school managers improve their creativity, flexibility, and networking skills.