This study investigated household education expenditure on Senior Secondary School (SSS) students in Osun State, Nigeria. The descriptive research design was adopted. Four local government areas (LGAs), representing 40%, were randomly selected from each of the three senatorial districts in the state. There were 142 public senior secondary schools in the 12 sampled LGAs. Forty per cent of the schools were randomly selected per LGA, totaling 56. Forty percent of SSS III students were randomly selected per school, totaling 3,304. The instrument titled: “Household Education Expenditure Scale” (r=0.97), used for the study was filled by parents of sampled students. Two research questions were answered. Data were analysed using descriptive statistics. From the results, 91.6%, 85.6%, 91.2% and 70.82% of the households spent part of their income on students’ textbooks, transportation, food and extra lessons, respectively despite the free education programme of the state government. The study concluded that free education in Osun State is not totally free for households. Household education expenditure is a determinant of students’ participation in secondary education in the state. Free education should focus more on alleviating households’ burdens by providing students with textbooks, transport, feeding at school and quality of instruction. Households in the state should be empowered economically to be able to take good care of their children.