Homegardens are traditional, small-scale farming systems that play a vital role in household food and nutrition security, particularly in rural areas. In southwestern Uganda, farmers manage homegardens as diverse, intercropped banana-based systems that provide continuous harvests, yet data on their food plant diversity and contribution to nutrition remain scarce. This study addresses that gap by assessing 102 randomly selected homegardens across three regions in southwestern Uganda. Plant species inventories were conducted in gardens averaging 0.18 hectares, alongside 601 multiple-pass 24-hour dietary recalls, 102 Household Food Insecurity Access Scale (HFIAS) questionnaires, and anthropometric measurements of 231 individuals. Results revealed 250 plant species across gardens, with a mean of 24 species per garden and a Shannon diversity index averaging 1.32. Notably, 97% of individual plants and 50% of species were cultivated for food. Homegardens accounted for 90% of foods reported in dietary recalls. Despite this, food insecurity persisted, with an average household hunger score of 4.9 and a high stunting rate (44%) among children under five. Adult BMI data showed 16% underweight and 17% overweight/obese. Dietary diversity was moderate, with an average score of 7.1 out of 12. A weak but significant negative correlation was found between plant species richness and hunger score (r = -0.262, p = 0.008), indicating that greater plant diversity is associated with reduced hunger. While homegardens are critical for food access, their potential for improving nutrition could be enhanced by integrating micronutrient-rich crops. Ongoing multivariate analyses aim to identify socio-economic factors influencing dietary outcomes.