Tomislav Merčep (born 28 September 1952) is a former Croatian politician and paramilitary during the Croatian War of Independence.
A native of Vukovar, Merčep worked as an engineer before joining the Croatian Democratic Union (HDZ) in 1990. He then entered the local city government as the Secretary of People's Defense (Croatian: Sekretar narodne obrane), where he exerted considerable power in the local police and business, esp. in preparation for the impending war. During the war, he engaged in paramilitary activities which were subsequently investigated by the Hague tribunal and covered by the (now defunct) Croatian newspaper Feral Tribune.
At the turn of 1991, several properties owned by ethnic Serbs were blown up in Vukovar, and it was widely speculated that Merčep was behind this. In 1997 Feral Tribune released a document which confirmed exchanges of large quantities of explosive materials in September 1990 between Merčep and Branimir Glavaš. In August 1991, Merčep was briefly arrested by Croatian authorities and detained on undisclosed charges, but was soon released and moved to Zagreb together with his family, a week before the Battle of Vukovar started.
Merčep later became an officer in the Croatian Ministry of Internal Affairs and he participated in the other fronts of the Croatian War of Independence, being in command of thousands of paramilitaries which were responsible for killing and expelling thousands of ethnic Serbs from areas in and around Gospić, among other places (notably the Murder of the Zec family in Zagreb). A decade later, five members of his unit, Munib Suljić, Igor Mikola, Siniša Rimac, Miro Bajramović and Branko Šarić, were indicted on several criminal charges related to the so-called "Pakračka poljana" case, involving the killing of prisoners, mostly ethnic Serbs, in a field near Pakrac, and later convicted. Tomislav Merčep himself was not indicted in these proceedings.