In this study, the effects of alkaline stress on germination growth of grass pea (Lathyrus sativus L.) were investigated. As plant material landraces 2006, 4403 and 1603 and the registered varieties GAP Blue and İptaş were used. Alkali stress was generated using Na₂CO₃ and applied at 6 concentrations 0, 10, 20, 30, 40 ve 50 mM).  The study was arranged as split plot design with 3 replications, and 20 seeds from each genotype were placed in a petri dish and 10 ml of Na₂CO₃ solution was added to the petri dishes. Then, the petri dishes were tightly covered with parafilm and allowed to germinate in the dark environment at 20 ± 1 ° C for 7 days in the climate room. In the experiment, germination speed, germination rate, root length, shoot length, root fresh and dry weights, seedling vigour index and ODAP content were examined. it was determined that 1603 local populations respond well to alkali stress as well as varietie in terms of the investigated traits. The 1603 local populations responded well to alkali stress as well as varietie in terms of the investigated traits. It was observed that the plants had an acceptable germination development even at 20 mM alkali doseBesides, it was determined that the ODAP content decreased with increasing doses and was below the level that would adversely affect animal health in all genotypes and doses. Accordingly, it was determined that the grass pea was positively affected by mild alkali stress, and the results obtained from the study shed light on future studies.