Vulkan may refer to:

• Vulkán, the Hungarian name for the city of Vulcan, Hunedoara, Romania
• SMS Vulkan, a German U-boat salvage tug
• R-25 Vulkan, a Yugoslav surface-to-air missile project
• Bremer Vulkan, a former German shipbuilding company located at the Weser river in Bremen-Vegesack
• AG Vulcan Stettin and Vulcan-Werke Hamburg und Stettin Actiengesellschaft, a former German shipbuilding and locomotive building company (also spelled Vulkan)
• Vulkan (API), an open standard API for explicitly accessing GPU graphics and compute acceleration

Vulcan (; formerly Jiu-Vaidei-Vulcan; , Zsilyvajdejvulkán (Zsily-Vajdej-Vulkán); ) is a city in Hunedoara county, Romania. With a population of 22,906, it is the second-largest city in the Jiu Valley. It administers two villages, Dealul Babii ("Old Woman's Hill" in Romanian; Hegyvulkán) and Jiu-Paroșeni (Zsilymacesdparoseny).