Cassius Apronianus or Apronianus (died 180) was a Roman who lived in the 2nd century. He was a member of Cassius , one of the oldest families in Ancient Rome.
Apronianus was a Roman of senatorial rank. Apronianus was originally from Bithynia (modern North-Western Turkey). Through his political career, at different periods he was a Roman Proconsul (or Governor) of Cilicia (modern Southern-Eastern Turkey) and Dalmatia (modern Dalmatia, Croatia), during the Nerva-Antonine Dynasty in Rome.
Apronianus married the daughter of Greek historian, orator, and philosopher Dio Chrysostom. Their son was Roman historian, consul and senator Cassius Dio. The year that he died, Apronianus was admitted into the Roman senate.