Maize (Zea mays), a staple food in Kenya, is vital for food security and economic sustainability, contributing 12.65% to the agricultural GDP. Despite its centrality, limited studies have explored the nutritional composition of maize varieties grown in Kenya. This study bridges the gap by applying Attenuated Total Reflectance Fourier- Transform Infrared (ATR-FTIR) spectroscopy and chemometric analysis to evaluate the macronutrient content (starch, proteins, and lipids) of 15 maize varieties cultivated in Kirinyaga County: Makueni, Duma 43, Sungura 301, Pioneer 3253, Pioneer 3506, Pioneer 3218, Pioneer 3812, Pannar 3M05, Dekalb 777, Dekalb 8031, Dekalb 8033, Dekalb 9089, Aminica 505, Tsavo 3106, and Ken Agro 5117. Using spectral data in the 4000–500 cm⁻¹ range, key absorption bands were identified for starch (997, 1076, 1149 cm⁻¹), proteins (1519, 1539, 1646 cm⁻¹), and lipids (1746, 2854, 2925 cm⁻¹). Principal Component Analysis (PCA) explained 95.53% of the data variance, grouping maize varieties into clusters that highlighted genotypic similarities and differences. Heatmaps visualized nutrient distribution, identifying Ken Agro 5117 as the most nutrient-dense variety, while Duma 43 exhibited lower levels of starch, proteins, and lipids. The results emphasize the predominance of genetic factors in determining nutritional profiles, though agronomic practices contribute to variability. This study demonstrates the efficacy of ATR-FTIR spectroscopy as a rapid, cost-effective tool for nutritional profiling, offering valuable insights into optimizing maize varieties for dietary and ecological suitability