Mario Brnjac (October 3, 1944 – September 24, 2007) was a former Croatian football player.
Born in Sveta Nedelja, Istria, as a player he spent nine seasons with HNK Rijeka.
He was one of the key defenders for Rijeka during much of the 1960s and the early 1970s, collecting over 300 caps.
In 1972, he moved to Borac Banja Luka where he played for four more years before retiring.