Turkey is of great importance for the biodiversity of genus Onobrychis Adans. and hosts 55 species that are adapted to dry and poor environments. This study was conducted to evaluate 35 Onobrychis taxa in terms of 1000-seed weight, germination percentage, mean germination time, and hard and swollen seeds and to determine the suitability of mechanical scarification for dormancy breaking in species with hard or impermeable seed coats. Seed dormancy was detected in 19 of the investigated species and 14 of the endemic species. Germination percentages of these taxa ranged from 5.5% to 98.0%. The lowest germination rate (5.5%) and the highest hard seed rate (93.0%) were determined in Onobrychis lasiostachya Boiss. Increased germination and decreased hard seed rates were achieved using mechanical scarification with sandpaper in Onobrychis gracilis Besser. Germination of O. lasiostachya, Onobrychis oxyodonta Boiss., and Onobrychis podperae Sirj. increased after mechanical scarification. It was concluded that mechanical scarification is an effective method for improving germination of wild Onobrychis taxa.