Millie Davis
Ms. O (109 eps)
Dalila Bela
Agent Olive (109 eps)
Isaac Kragten
Otis (109 eps)
Christian Distefano
Owen (109 eps)
Filip Geljo
Agent Otto (109 eps)
Anna Cathcart
Agent Olympia (109 eps)
Sean Michael Kyer
Agent Oscar (109 eps)
Eshaan Buadwal
Olaf (109 eps)
Olivia Presti
Oona (63 eps)
Jaiden Cannatelli
Olhm (15 eps)
Jaeden Noel
Agent Obfusco (7 eps)
Kyle Gatehouse
Monsieur Papier-Maché (6 eps)
Martin Roach
Fladam (4 eps)
Drew Haytaoglu
Ozric (3 eps)
Percy Hynes White
Odie (3 eps)
Ellery Miki-Petite
Arctic Mr. O (2 eps)
Sharron Matthews
Chef Sylvia (2 eps)
Tomaso Sanelli
Agent Ogg (1 eps)
Raphael Alejandro
Agent in Band (uncredited) (1 eps)
Miguel Anthony
Tony (1 eps)
Alexander Elliot
Agent O'Que (1 eps)
Kyle Meagher
Not The Real Big O (1 eps)
Jacob Soley
Osmond (1 eps)
Sarah Abbott
Yucks (1 eps)
Logan Aultman
Seattle Creature Agent (1 eps)
Fodé Bangoura
Dad (1 eps)
Aaron Eves
High Five (1 eps)
Tyler Malazo
Evil Newsboy (1 eps)
Thom Allison
Chef (1 eps)
Kevin Hanchard
Dry Cleaner Guy (1 eps)
Jameson Kraemer
King Pin Mike (1 eps)
Mercedes Morris
Corn Flakes (1 eps)
Ann Pirvu
Evil Queen (1 eps)
Eric Toth
Gerrard (1 eps)
Ana Araújo
Chief of Graph (1 eps)