Pope Dionysius (died 268) was a Greek pope.
Saint Dionysius may also refer to:
- Saint Dionysius of Alexandria (died 265), Bishop of Alexandria
- Saint Dionysius of Corinth (died c. 171), Bishop of Corinth
- Saint Dionysius of Paris (died c. 250), Christian martyr
- Saint Dionysius the Areopagite (1st century), judge of the Areopagus
- Geevarghese Dionysius of Vattasseril or Saint Dionysius of India (died 1934), Primate of the Indian Orthodox Church