Pumpkin is usually cultivated in arid and semiarid regions, and the lack of water stress-tolerant cultivars is a major limiting factor. Therefore, this study was carried out to identify superior water stress-tolerant genotypes. For this purpose, 44 inbred lines with superior agronomic traits were selected from the gene pool. In addition, two hybrids (G1-Mert Bey F1 and G2-Sena Hanim F1) and two landraces (G3-Hatun Tırnağı and G4-Cercevelik) with high commercial value were used as commercial cultivars. The water stress indices were calculated from seed yields from the pumpkin genotypes grown in irrigated and water stress conditions in 2017 and 2018. The stress tolerance index (STI) determines tolerant and superior genotypes. From the principal component and cluster analyses’ findings, G9, G40, G32, G36, G5, G11, G22, G30, G37, and G13 showed the highest water stress tolerance among the inbred lines. During future breeding experiments, these inbred lines may have significant potential for developing novel water stress-tolerant cultivars for pumpkin cultivation in semiarid regions.