Viadukt is a Croatian civil engineering company, specialised in the areas of bridge, tunnel and road engineering. Other business activities of the company include construction and reconstruction of urban streets.

The most significant works performed by the company include: significant sections of the A1, A3 and A5 motorways, a number of motorway viaducts, including Osojnik, Draga, Ze?eve Drage,Dobra, Dre?nik, Limska Draga etc., as well as Bajer Bridge (a part of the A6 motorway) and Sava River Bridge (a part of the A2 motorway). The company is also employed for execution of the construction works at the Pelješac Bridge.  Also, the company has executed a number of significant tunnels, including Tuhobić Tunnel, the longest tunnel on the A6 motorway.