Poverty and food insecurity continue to feature prominently in the global agenda, with particularly close attention being paid to the determinants of food insecurity. However, the effect of education is mixed and remains understudied in low income countries. Using longitudinal data collected between 2007 and 2012 in Kenya, we investigated the effect of household education attainment on food security among poor urban households. Household food security was constructed from a set of four key items while education was the average years of schooling for individuals aged 18 years and above in a household. To determine the association between education attainment and food security, we fitted a random effects generalised ordered probit model. The prevalence of severe food insecurity ranged from 49% in 2008 to 35% in 2012. The ordered probit results showed a significant effect of education on food security. The probability of being food insecure decreased by 0.019 for a unit increase in the average years of schooling for a given household. The effect of education, remained significant even after controlling for household wealth index, a more proximate determinant of food security in a cash-based economy such as the urban slums. The findings highlight the need to focus on the food security status of the urban poor. Specifically, results suggest the need for programs aimed at reducing food insecurity among the urban poor and enhancing household livelihoods. In addition, investment in the education of the slum households may, in the long term, contribute to reduction in the prevalence of food insecurity.