The purpose of this study was to examine the effects of sand harvesting on environment and educational outcomes in public primary schools in Kathiani Sub-County, Machakos County, Kenya. This study was premised on treadmill theory of production proposed by Schnaiberg (1980). The study adopted a survey design. Combinations of purposive and stratified random sampling was utilized in selecting 10 headteachers, 10 class teachers, 80 pupils, 2 local administration officer and 2 education officer yielding a sample size of 104 to participate in the study. Data collection instruments were questionnaires and interview guides. The findings of the study were that sand harvesting had a profound negative impact on the environment ranging from destruction of water sources to soil erosion, and destruction of the infrastructure. Public primary schools in Kathiani District were also recording declining education standards in terms of low enrolment retention rates resulting in low academic outcomes in schools in the study locale. It was recommended that the devolved County Government of Machakos County and other stakeholder should regulate sand harvesting activities in order to minimise negative impact on the environment, educational outcomes and overall internal efficiency of schools in areas where the activities are conducted.