The city name means literally "Tomislav town". The name was changed from Duvno in 1928 by King Alexander I of Yugoslavia in tribute to his son Prince Tomislav and also in tribute to King Tomislav of Croatia, first king of the Croatian Kingdom. The name was restored to Duvno after World War II Socialist Federal Republic of Yugoslavia. During the 1990s it was once again changed to Tomislavgrad. Still, among inhabitants of Bosnia and Herzegovina, the local residents are often referred as Duvnjaci ("Duvniaks") and the town is often called Duvno. Also, the town is sometimes referred to simply as "Tomislav". The Roman Catholic diocese in that area is still called Mostar-Duvno. During the Roman Empire the city was called Delminium and during the Kingdom of Croatia, Županjac. Under the Ottoman Empire, it was called Županj-potok and in Austria-Hungary, Županjac.