This paper investigates the effect of land ownership security on agricultural productivity, specifically maize yield. It applies a Random Effect Model on a balanced panel sample size of 672 smallholder maize farmers derived from the last two waves of the Tanzania National Panel Survey (TNPS) data, which were collected in 2014/2015 (wave 4) and 2019/2020 (wave 5). The empirical results reveal that land ownership security is a significant factor in promoting agricultural productivity. Moreover, the results indicate that gender, farm size, education, and improved agricultural technologies significantly influence maize productivity. Thus, policies aimed to promote legal land ownership security are important in boosting smallholder farmers’ agricultural productivity and food security.