A
- Philip Abbott ("Long Distance Call" and "The Parallel")
- Casey Adams ("It's a Good Life")
- Dorothy Adams ("Dust")
- Mary Adams ("Twenty Two")
- Stanley Adams ("Once Upon a Time" and "Mr. Garrity and the Graves")
- Louis Adelin ("An Occurrence at Owl Creek Bridge")
- Jay Adler ("The Jungle" and "He's Alive")
- Luther Adler ("The Man in the Bottle")
- David Ahdar ("The Silence") (uncredited)
- Brian Aherne ("The Trouble With Templeton")
- Charles Aidman ("And When the Sky Was Opened" and "Little Girl Lost")
- Claude Akins ("The Monsters Are Due on Maple Street" and "The Little People")
- John Alban ("The Silence") (uncredited)
- Jack Albertson ("The Shelter" and "I Dream of Genie")
- Hardie Albright ("To Serve Man")
- Frank Aletter ("The Parallel")
- Denise Alexander ("Third from the Sun")
- Clark Allen ("Five Characters in Search of an Exit")
- Elizabeth Allen ("The After Hours")
- Sheldon Allman ("The Monsters Are Due on Maple Street")
- Frank Allocca ("What You Need") (uncredited)
- John A. Alonzo ("Dust") (credited as John Alonso)
- Totty Ames ("You Drive")
- John Anderson ("A Passage for Trumpet", "The Odyssey of Flight 33", "Of Late I Think of Cliffordville" and "The Old Man in the Cave")
- Dana Andrews ("No Time Like the Past")
- Edward Andrews ("Third from the Sun" and "You Drive")
- Tod Andrews ("The Bewitchin' Pool")
- Richard Angarola ("Miniature")
- John Archer ("Will the Real Martian Please Stand Up?")
- David Armstrong ("I Sing the Body Electric" (uncredited), "The Trade-Ins", "To Serve Man" (uncredited) and "The Rip Van Winkle Caper" (uncredited))
- R.G. Armstrong ("Nothing in the Dark")
- Phil Arnold ("Mr. Dingle, the Strong")
- John Astin ("A Hundred Yards Over the Rim")
- Malcolm Atterbury ("Mr. Denton on Doomsday" and "No Time Like the Past")
- Barry Atwater ("The Monsters Are Due on Maple Street")
- Renee Aubry ("Sounds and Silences")
- Jacques Aubuchon ("Valley of the Shadow")
- Eleanor Audley (voice only) (uncredited) ("The Hitch-Hiker")
- Pamela Austin ("Number 12 Looks Just Like You")
- Val Avery ("The Night of the Meek")
Read more about this topic: List Of The Twilight Zone (1959 TV Series) Guest Stars