Acacius was a cognomen of Rome, and the name of various saints:

• Saint Acacius of Byzantium (d. 303)
• Saint Acacius
• Saint Acacius of Amida
• Acacius of Caesarea "the One-Eyed" (d. 366)
• Acacius of Beroea
• Acacius of Constantinople (d. 489)
• Acacius, father of Theodora

The acacia is a type of thorny tree.