The contribution of homegardens to the food and nutrition security of rural farmers has rarely been explored empirically. Our study assesses the influence of homegarden agrobiodiversity, production system parameters, and socioeconomic factors on household dietary diversity and anthropometric conditions in southwest Uganda. Plant inventories of 102 homegardens were followed by two 24-h recalls (n = 589) and anthropometric measurements (n = 325) of household members, as well as household food insecurity questionnaires (n = 95). Regression models explained between 16 and 50% of variance in dietary diversity and between 21 and 75% in anthropometric measurements. Results indicate that supporting diverse homegarden systems can in part reduce food insecurity in Uganda. We conclude with recommendations for further strengthening the role of homegardens in improving dietary and anthropometric outcomes.