W.I.T.C.H. is an animated series based on an Italian comic book series of the same name. The series follows the adventures of five girls known as the Guardians (Will, Irma, Taranee, Cornelia, and Hay Lin) who gain elemental magical powers to protect Earth and other worlds from evil. The series originally aired from December 18, 2004 until December 23, 2006. 52 episodes were produced, over two seasons. Greg Weisman became the show's producer and story editor in its second season. Cary Bates and Jon Weisman each wrote four episodes of the series.
The following voice actors appeared in both Gargoyles and W.I.T.C.H. They are listed alphabetically by surname.
- Thom Adcox - Sammy (episode: "C is for Changes")
- Ed Asner - Napoleon
- Michael Bell - Crimson, Drake, Blunk's mother
- Val Bettin - Herbert Olsen
- Jeff Bennett - Tracker
- Rocky Carroll - Jerry, Bitterroot
- Cam Clarke - Dean Collins
- Jim Cummings - Tridart, Howard Hale
- Pat Fraley - Marco
- Elisa Gabrielli - Sarena Sanchez
- Dorian Harewood - Lionel Cook
- CCH Pounder - Kadma
- Justin Shenkarow - Eric Lyndon
- Kath Soucie - Nerissa, Sandpit
- Cree Summer - Ember
- B.J. Ward - Halinor, The Mage
- Frank Welker - Additional voices
References to Gargoyles in W.I.T.C.H.
- In the episode "I is for Illusion", written by Cary Bates, one of the Guardians asks "How are we supposed to beat up a beach?" while fighting the villain Sandpit. This is a direct reference to the Archmage's line ("After all, what have you achieved? You beat up a beach!") from "Avalon" Part Two. 
- In the episode "U is for Undivided", also written by Cary Bates, two characters appear named Brenda and Marco. These characters are based on Brendan Quarters and Margot Yale. Pat Fraley voiced both Brendan and Marco. 
- A character in the series is named Gargoyle, although he shares few characteristics with the species from Gargoyles. 
References to W.I.T.C.H. in Gargoyles
- In "Strangers", the first issue of Gargoyles: Bad Guys, the song playing on the boombox during the framing sequence at the start and during the Sydney scenes is "The Will To Love". This song was written by Greg Weisman for the second season of W.I.T.C.H., and it is performed in the episode "S is for Self" as a love song composed for the Guardians' leader Will Vandom by her boyfriend Matt Olsen. Greg Weisman has mentioned a private theory that the song is from the W.I.T.C.H. TV series that aired within the Gargoyles Universe, although it would have done so about a decade before its original airdate in the real world. 
- In "Religious Studies 101: A Handful of Thorns" one of Mysterio's Homunculi is called 'Blunk', named for the small goblin-like creature that acted as the series' comedic sidekick. That Homunculus and Blunk were both voiced by Steve Blum.