K
- Madeline Kahn
- Carol Kane
- Julie Kavner (as Marge Simpson)
- Alicia Keys
- Nicole Kidman, demonstrating the word "stubborn"
- Richard Kind (Playing a Balloon Fairy in episode 4088)
- B.B. King
- Larry King
- Greg Kinnear, demonstrating the word "machine"
- Reverend Frederick Douglass Kirkpatrick
- Kevin Kline
- T.R. Knight - Letter "I" - Private I
- Heidi Klum - Compliments with Elmo
- Diana Krall
- Alison Krauss
- Kronos Quartet
- Mila Kunis - teaches the word "include" with Elmo
Read more about this topic: List Of Guest Stars On Sesame Street