This article shows how interventions to provide Universal Primary Education (UPE) from the 1970s into the twenty-first century affected efforts to improve the quality of primary education in Kenya and Tanzania. While the interventions have made significant differences in the lives of many communities by increasing access to education of children who would have been denied schooling, quality indicators (including attrition and completion rates and examination scores) have stagnated at best or declined. Efforts to ensure and maintain quality in primary education in the two countries are reported to face serious challenges, including mainly inadequate funding to ensure the provision of essential teaching and learning materials, appropriate infrastructure as well as a sufficient number of competent teachers.