Bostankaya is a village in Ulaş District, in Sivas Province, Türkiye. Bostankaya lies at 1,364 m above sea level, 7.2 km from the Deli Dağ mountains. It has 254 inhabitants. The nearest city is Sivas, 27 km to the north. Among the landmarks around are Gök Medrese (26 km), Great Mosque of Sivas (26 km) and Buruciye Medrese (27 km).