Six male Titans are listed in Hesiod’s Theogony. They are Oceanus, Coeus, Crius, Hyperion, Iapetus, and Cronus.
Hesiod presents the Titans as twelve children of Gaia, the Earth, and Uranus, the Sky. The group contains six males and six females, the latter often called Titanesses: Theia, Rhea, Themis, Mnemosyne, Phoebe, and Tethys. This twelve-member list is the standard Hesiodic genealogy.
The Titans belong to the generation before the Olympian gods. Cronus, the youngest male Titan, overthrew Uranus with Gaia’s help and became ruler. Later, Zeus and his siblings fought Cronus and the older gods in the ten-year Titanomachy. Some Titans, including Oceanus, did not necessarily fight on Cronus’s side.
A common mix-up is counting famous descendants such as Atlas, Prometheus, Helios, or Leto as members of the original twelve. Later authors sometimes use “Titan” more broadly, and Apollodorus gives a somewhat different genealogy, but Hesiod’s Theogony specifically identifies six male Titans.