The following species have members that serve in Starfleet. Their homeworlds may or may not be Federation members.

By appearance

• Abdon's species (DS9: "The Assignment")
• Alien crewman's species (TNG: "Data's Day")
• Andorian (Star Trek: The Motion Picture)
• Arkenite (Star Trek IV: The Voyage Home)
• Bajoran (TNG: "Ensign Ro")
• Bassoonist's species (TNG: "In Theory")
• Benzite (TNG: "Coming of Age")
• Betazoid (TNG: "Encounter at Farpoint")
• Betelgeusian (Star Trek: The Motion Picture)
• Bolian (TNG: "Conspiracy")
• Caitian (TAS: "The Survivor")
• Deltan (Star Trek: The Motion Picture)
• Unnamed alien doctor's species (Star Trek)
• Edosian (TAS: "One of Our Planets Is Missing")
• Efrosian (Star Trek IV: The Voyage Home)
• Elaysian (DS9: "Melora")
• Enterprise crewman with pointed eyebrow's species (Star Trek III: The Search for Spock)
• Ferengi (DS9: "Facets")
• Haliian (TNG: "Aquiel")
• Human (TOS: "The Cage")
• Klingon (TNG: "Encounter at Farpoint")
• Megazoid (Star Trek VI: The Undiscovered Country)
• Napean (TNG: "Eye of the Beholder")
• Nara's species (TNG: "Eye of the Beholder")
• Pardshay's species (Star Trek VI: The Undiscovered Country)
• Peliar Zel native (TNG: "The First Duty")
• Relativity helmsman's species (VOY: "Relativity")
• Rhaandarite (Star Trek: The Motion Picture)
• Romulan (TNG: "The Drumhead")
• Saurian (Star Trek: The Motion Picture)
• Tiburonian (DS9: "The Ship")
• Trill (DS9: "Emissary")
• Vulcan (TOS: "The Cage")
• Worene's species (Star Trek: The Motion Picture)
• Zaldan (TNG: "Coming of Age")
• Zaranite (Star Trek: The Motion Picture)

Alternate timelines, false realities and parallel universes

• Alnschloss K'Bentayr's species (Star Trek)
• Cardassian (TNG: "Parallels")
• Ferengi (TNG: "Future Imperfect")
• Kazon (VOY: "Living Witness")
• Keenser's species (Star Trek)
• Orion (Star Trek)
• Talaxian (VOY: "Living Witness")
• Xindi (ENT: "Azati Prime")

By reference

• Argosian (DS9: "Dax")
• Benzenite (DS9: "Apocalypse Rising")
• Tellarite (DS9: "Apocalypse Rising")
• Tyrellian (TNG: "Starship Mine")
• Vilix'pran's species (DS9: "Heart of Stone")