Allium decumbens Balos & Sonay is described as a new species from Elazığ Province, Eastern Türkiye. It is an endemic serpentine species that grows on the slopes at an altitude of 2160–2300 m above sea level on the Hazarbaba Mountain in the Sivrice district of Elazığ Province. Based on morphological features, it belongs in Allium subgen. Allium sect. Allium. Allium decumbens is quite different from other species in the section with some of its features. It is morphologically similar to A. murat-sonayii Balos, Sonay & C.Çeçen. However, it clearly differs from A. murat-sonayii by its leaf structure, tunic type, larger bulb, short and decumbent stem, number and shape of leaves, different sheath structure, longer pedicels, umbel structure with radial symmetry, and smooth inner and outer tepals. Herein, the morphology of A. decumbens, a comprehensive description, detailed photographs, habitat and ecological characteristics, and IUCN conservation assessment are provided.