The following is a list of debut (and first known) appearances of Sesame Street characters.
- Oscar the Grouch — Episode 0001.
- Jennie — Episode 0001.
- Granny Bird — First appears in Episode 0030 as the Big Bird puppet with a flowered hat, shawl, glasses and purse. Converses with Big Bird off screen.
- Granny Fanny Nesselrode — Episode 0112 (originally made from the Southern Colonel puppet; switched to Large Lavender Live Hand Anything Muppet pattern the following season)
- Grover — Episode 0125 in name (not fully-formed until season two); appeared earlier as a previously established monster (see: proto-Grover).
- Herry Monster — Episode 0131
- Farley — Episode 0131
- Larry and Phyllis — Episode 0131
- Willy — Episode 0131
- Mr. Johnson — Episode 0276
- Sam the Robot — Episode 0406
- Barkley — appeared in Episode 1177 and Episode 1184 as Woof Woof before being renamed in-show during the 10th season premiere.
- Elmo — Sesame Street Unpaved and Imagination Illustrated cite Elmo making his debut in 1979 as an Anything Muppet. The earliest-known instance of his name being used was in Episode 1439.
- Forgetful Jones and Clementine — Episode 1446; a season 12 press kit mentions them as new characters this season (Buster the Horse is also referred to as a new character, though the puppet had been around since at least 1974).
- Warren Wolf — A season 12 press kit refers to him as debuting this year.
- Honkers — A season 12 press kit refers to this as the debut season for the Honkers.
- Ferlinghetti Donizetti — A season 12 press kit refers to him as a new character this season.
- Dr. Nobel Price — A season 12 press kit refers to this as his debut season, appearing as early as Episode 1455
- Joey and Davey Monkey — Episode 2953 (40 Years of Life on the Street page 132 incorrectly cites Season 24 as their debut).
- Sherry Netherland — Episode 3136
- Ingrid — Episode 3136
- Ruthie — Episode 3136
- Carlo — Episode 3136
- Tarah — Episode 3136
- Celina — Episode 3136
- Murray Monster — debuts as a nameless monster interviewing kids. He would later get a name during Season 38.
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