HNK Vukovar '91 was a Croatian football club based in the river port of Vukovar. Under the name NK Vukovar '91, club was founded in Zagreb by Vukovar refugees during the Croatian War of Independence. In 1992, newly founded Vukovar '91 merged with NK Sloga, an older club based in Vukovar. The club's greatest success came in the 1998–99 season, when Vukovar won the Croatian second division, earning the team promotion to the Prva HNL. They lasted only one season in the top flight and were relegated after finishing last.