<p>Gray leaf spot (GLS) is a major foliar disease that limits maize productivity and nutritional quality in sub-Saharan Africa. This study evaluated 16 extra-early provitamin A Quality Protein Maize (PVA-QPM) inbred lines and two checks across two cropping seasons in Oke-Oyi, Nigeria, under natural infection augmented by artificial inoculation. Grain yield ranged from 2.60 to 4.10 t ha⁻¹, with TZEEIORQ-15 (4.10 t ha⁻¹), TZEEIORQ-07 (4.05 t ha⁻¹), and TZEEIORQ-03 (3.95 t ha⁻¹) exceeding the check Obatanpa by 57.7%, 55.8%, and 51.9%, respectively. GLS scores ranged from 3.0 to 7.8, while β-carotene varied from 5.5 to 18.0&#xa0;µg&#xa0;g⁻¹. Lysine, tryptophan, and protein contents ranged from 2.5 to 4.5&#xa0;mg&#xa0;g⁻¹, 0.50 to 1.00&#xa0;mg&#xa0;g⁻¹, and 7.3 to 9.7%, respectively. GLS exhibited genotypic and phenotypic coefficients of variation (GCV and PCV) of 19.8% and 22.5%, respectively, while grain yield recorded 11.5% and 13.2%, and β-carotene showed 26.5% and 29.8%. Broad-sense heritability were 0.77 for GLS, 0.76 for grain yield, and 0.79 for β-carotene, with corresponding narrow-sense heritability values of 0.54, 0.51, and 0.58. Genetic advances as a percentage of the mean were 34.2% for GLS, 20.1% for grain yield, and 46.0% for β-carotene. Principal component analysis explained 59.7% of total variation, with PC1 (38.2%) and PC2 (21.5%) separating genotypes based on GLS, grain yield, and β-carotene. GLS showed strong negative correlations with grain yield (<i>r</i> =  − 0.98) and β-carotene (<i>r</i> =  − 0.95). Marker analysis identified Xgdp12, Xgls5, and Xumc2147 as associated with GLS resistance, explaining 25–32% of phenotypic variation. These results indicate that the selected extra-early PVA-QPM inbred lines combine favourable agronomic performance, enhanced nutritional quality, and disease resistance, and can therefore be utilised as parental lines in breeding programmes in developing early-maturing, GLS-tolerant maize hybrids.</p>