The Apollo-class was an early 24th century Starfleet vessel. The Apollo was still in use by the 2370's, however has been almost completely phased out of service.

The actual design of the Apollo is unknown. In "Unification" the T'Pau along with three other Vulcan ships are listed as Apollo-class by the Star Trek: Encyclopedia.

The class name comes from Greek mythology and the Apollo space program which brought Humans to the moon.

USS Agamemnon NCC-11638
   Served in Captain Picard's blockade during the Klingon Civil War in 2368.
   Named after Greek mythological figure who commanded the Greek forces in the Trojan War.
   "Redemption" - TNG.
USS Ajax NCC-11574
   Tested an experimental warp drive technology in 2364. Served in Captain Picard's blockade during the Klingon Civil War in 2368.
   Named after two heroes from Greek mythology, Ajax of Salamis and Ajax of Locris who fought in the Trojan War.
   "Where No One Has Gone Before" - TNG. "Tapestry" - TNG. "Redemption" - TNG.
USS Clement NCC-12537
   Scheduled to rendezvous with the USS Enterprise NCC-1701-D in 2370.
   "Lower Decks" - TNG.
USS Gage NCC-11672
   Destroyed by the Borg at Wolf 359 in 2367.
   "The Best of Both Worlds" - TNG. "Emissary" - DS9.