Mladen III Šubić was a member of the Croatian Šubić noble family, who ruled from Klis Fortress. He was in possession of Klis, Omiš and Skradin. He is also known as Shield of the Croats, according to the Latin epitaph in verse on his grave in Trogir.

The Šubić family, also known initially as Bribirščić, was one of the Twelve noble tribes of Croatia and a great noble house which constituted Croatian statehood in the Middle Ages. They held the county of Bribir (Varvaria) in inland Dalmatia. They with their prominent branch Zrinski (1347–1703) were arguably the leading noble family of Croatia for almost 500 years.