Whose Line Is It Anyway? (sometimes referred to as Whose Line? or WLIIA) is an improvisational comedy show. It originated as a British radio show, but was then transferred to British TV, where it was hosted by Clive Anderson (1988-1998), and eventually American TV, hosted by Drew Carey (1998-2007), then Aisha Tyler (2013-present). The show's games (both British and American versions) have referenced the Muppets several times.
- In the game Film and Theatre Styles, Muppets or Sesame Street were frequently used styles. (e.g. Ryan re-enacts One of These Things with his guns as he hijacks Sam Johnson's plane.  Another had Greg explain to Caroline Quentin how to shoplift.  Yet another scene had Ryan as Kermit in the Africa mist being told to come back. )
- In a game of Whose Line, Ryan Stiles and Colin Mochrie discuss Ryan's pre-wedding jitters. Colin calls his bride-to-be a tramp saying that "She's had more hands up her than the Muppets!"
- In the second episode of season 1, during a game of "Let's Make a Date," Ryan Stiles was a man with an alien coming out of him. Brad Sherwood guessed he was either that or Jim Henson.
- In a season 3 episode, Wayne Brady and Chip Esten reference Sesame Street in a game of "Props" by holding two parenthesis-style pieces together. One of them says, "Today's show was brought to you by the number 8!". In a Sixth Season episode featuring the "Props" game, Wayne and Greg Proops are on one side. One of them references Sesame Street by forming a letter O and announces the traditional "brought to you by the letter/number" line.
- In a 5th season episode, in the game "Scenes From a Hat", a suggestion reads: "If lessons of love and sex were taught in the style of Sesame Street." Wayne puts on a Latin accent for "cerrado/abierto", Colin Mochrie wants to take a look at Big Bird, Colin, Kathy Greenwood, and Wayne re-enact the One of These Things segments, and Colin and Ryan form a (reverse) letter H. This joke is later referenced in "Jeopardy! questions where the Whose Line cast members are the answers" (Wayne: "Reasons Why the Letter 'H' Will Keep Me Up For Years to Come"), "Bad things to say as you're about to kiss her" (Colin to Kathy: "I was once part of the letter 'h'."), the Police Officer Hoedown (Colin: "I was once the best cop in all the land. People as they saw me would go 'Boy, is he grand.' I was so respected, believe me I'm not lyin' till I got fired for making an 'h' with Ryan.")  in the same episode.
- In another season 5 episode, a game of "All in One Voice" had two panelists on one side each, portraying a couple. Brad and Ryan sang as Kermit the Frog, and Wayne and Colin sang as Miss Piggy. 
- In an episode from the 7th season, Kathy Greenwood sings part of "Rubber Duckie" in Scenes From a Hat ("Bad songs to sing while making love").
- In a game of "Hats", Ryan had on a frog mask that resembled (but wasn't) Kermit. 
- In a game of "Props", during Season 4, a large red pompom-like object is used. At one point, Wayne pumps it into the air and chants, "Animal!" Another game had Greg hold a foam ring to his head as Cookie Monster.  Yet another had Ryan hold up two pieces as Oscar's eyebrow. 
- At the end of one episode, the cast is told to read the credits as if they were wild animals attacking the screen. Once again, Wayne refers to Animal, chanting his name and running wildly toward the screen. At the end of another one, the credits were read as Colin having a bachelor party and Jeff says they'll "make an 'H' out of you", refering again to the letter "h" gag.
- After one break, Drew says he, too, has a hand up his butt. 
- In another game of Props, Ryan Stiles, holding two gangly-looking props, says "Big Bird and the wife passed out." Yet another had Wayne hold a yellow boa, with Brad connecting the ends saying, "Big Bird has a hernia." The audience predictably groans.  One game in the revival with Aisha had Wayne hold up something he uses as Snuffy's trunk ("Big Bird, I'm so sad.") 
- One playing of "Film, TV & Theatre Styles" had the style of Sesame Street. Ryan imitates Count von Count, Colin imitates Oscar the Grouch and Wayne acts as Ernie, Grover (referencing his famous "Near and Far" sketch) and repeats the cerrado/abierto gag. An earlier playing on the eleventh episode of season 1 had Greg ask the audience if they can spell "bee". 
- In the revival, one Scene From a Hat was "If Sesame Street characters appeared on other shows"; Ryan was Big Bird on The Apprentice, Nyima was Cookie Monster on one of Gordon Ramsey's cooking shows, Colin repeated Grover's Near and Far sketch with Ryan as a zombie from The Walking Dead. Wayne as Elmo claims that since he "killed the opposing families, I've won the Game of Thrones."
- Another suggestion was "If Sesame Street were a soap opera"; Wayne was Snuffy asking Big Bird (Colin) for more OxyContin, Jeff was the Count telling Big Bird (this time Ryan) that he has "one tumor, two tumors, 1-2-3. Ha-ha-ha! Three tumors!" Colin once again does Near and Far, Wayne repeats cerrado/abierto and Colin claims he's carrying Wayne's child. Jeff as Ernie tells Bert (Ryan) that he's straight. Ryan bends him over the exact same way he did with Colin as the letter "h". Wayne piles on ("Capital H"). Aisha comforts Jeff ("I don't want to be on the show anymore.") and slaps him ("Really got used.") As with Colin, the joke is refered to in "Chants Schoolgirls Never Sing During Jump Rope". (Wayne: "I'm a good girl and I'm gonna be that way. I'm a good girl; stay back is what I say. Mmm-hmm. And you bet I will never be a captial 'H' in a man's alphabet.")
- In that same episode, the special guest, Robbie Amell, was refered to as a hot version of the Count, after a game of Duet where Wayne and Jeff sang as One Direction and he asked how many were in the band while improvising a rap, which also led to the "count to 5" gag for the episode.
- In yet another SFAH, Ryan forms the letter "E" as "if famous TV shows had been performed in the nude."
- The Muppet Babies episode title "Whose Tale Is It, Anyway?" is a nod to the show.
- When Wayne Brady appeared on Sesame Street in a 2003 episode, Elmo asks him to show between. Wayne was unaware of this, but Elmo encourages him, saying he's good at making things up on the spot, a reference to Wayne's musical presence on the show.
- Wayne Brady - Is a regular panelist on the American version.
- Sid Caesar - Made one special appearance in a season 5 episode of the American version.
- Stephen Colbert - Had two appearances on the American version.
- Dawn French - Appeared once on the radio version of Whose Line?.
- Stephen Fry - Several appearances on the British version.
- Whoopi Goldberg - Appeared twice on the American version.
- Kathy Griffin - Four appearances on the U.S. version.
- David Hasselhoff - Made one appearance on the U.S. version.
- Florence Henderson - Made one appearance on the American Whose Line.
- Eddie Izzard - One appearance on the British version.
- Chris Langham - Appeared once on the U.K. version.
- Lassie - Made one guest appearance on the U.S. version
- Hugh Laurie - One appearance on the radio version.
- John Sessions - Appeared regularly on the British Whose Line.
- Richard Simmons - Made one special guest appearance on the American version.
- Robin Williams - One guest appearance in an episode of the U.S. version.