The Mostar derby (Bosnian: Mostarski gradski derbi) is a football rivalry in Mostar, Bosnia and Herzegovina between HŠK Zrinjski and FK Velež. The derby took place for the first time in 1922 and is the oldest major football derby in Bosnia and Herzegovina.
Both Mostar clubs are among the oldest in the country. HŠK Zrinjski (Croatian: Hrvatski športski klub Zrinjski, English: Croatian Sports Club Zrinjski) was formed in 1905 while FK Velež was formed in 1922. However, the clubs had vastly different histories. Zrinjski was a reasonably successful club in the first half of the century, but was banned by communist Yugoslav authorities for competing in the 1. HNL under the Ustaše regime during World War II. At this point its records, along with those of other Croatian clubs, were destroyed. On the other hand, FK Velež thrived during the Yugoslav communist period, winning the Yugoslav Cup in 1981 and 1986.
After the independence of Bosnia and Herzegovina, Zrinjski was reestablished. At the same time, war broke out in the county. Over the course of the war and in its aftermath Mostar became a divided city with the Croats holding the west side and the Bosniaks the east, with those remaining Serbs living in the east as well. Zrinjski took over Velež's Bijeli Brijeg Stadium, as it was located deep inside the informal Croat territory of the Federation of Bosnia and Herzegovina, thus forcing Velež to move to Vrapčići stadium (later renamed to Rođeni Stadium).
The two clubs did not meet until 2000 for their first game. This happened because the nation's three ethnic groups each ran their own parallel leagues up until that point, with Velež in the Bosnian First League and Zrinjski in the First League of Herzeg-Bosnia