This study was aimed to investigate vegetative growth indicators of four oat cultivars (Genzania, Shefa, Carrolup, and Hamel) at seeding rates of 80, 100, and 120 kg ha⁻¹ in a factorial experiment within a randomized block design during the winter season 2022-2023. Genzania showed significant superiority in leaf area, relative growth rate (0.0707 g g⁻¹ day⁻¹), and total dry mass (21.54 tons ha⁻¹). Shefa excelled in tiller count (365.10 tillers m⁻²), while Hamel exhibited superiority in stem diameter (5.68 mm), lower lodging index (39.90), and fewer effective tillers (88.10%). Seeding rate effects included increased plant height and total dry mass, with a rise in lodging index. The highest seeding rate (120 kg ha⁻¹) significantly outperformed in tiller count. Conversely, leaf area and effective tiller percentage decreased with higher seeding rates. The 80 kg ha⁻¹ seeding rate showed superiority in relative growth rate. Interaction between factors was significant for total dry mass and lodging index, with Genzania × 120 kg ha⁻¹ performing the best. Cultivars varied in vegetative growth responses to seeding rates.