Over the years Oscar the Grouch has had many pets. His diverse menagerie includes various dogs, a cat, a pig, several elephants, and a donkey. His favorite pet is his worm, Slimey. Similar to a pet, Oscar builds Charles the Robot to follow his every command.
- Episode 0524, Episode 0590 and Episode 0619 — Frank, a fly.
- Episode 0700 — Rosebud, a skunk.
- Episode 0793 — Grover offers to become Oscar's pet, however it doesn't work out.
- Episode 1055 — Freddie, a fly.
- Episode 1266 — Moby Richard, a whale.
- Episode 1269 — Chloris, a cow.
- Episode 1441 — Oscar feeds multiple cows, horses, chickens, and pigs in his can.
- Episode 1449 — Oscar tells Telly and Susan that he has a whole flock of moths in his can, which he gives holeless shirts to munch on.
- Episode 1489 - Anthony, a tiger
- Episode 1552 - Myrna, a cow
- Episode 1555 - Sophie, a skunk
- Episode 1618 - Hedda, a hippo
- Episode 1740 — Oscar mentions he has hippos who reside in his swimming pool.
- Episode 2971 — Jezabel, a chicken; and Fred, a fish.
- Elmo's World: Farms — an entire farm in his can.
- Episode 2269 — Moby Jane, a whale (mentioned).
- Episode 3664 — Portia, a rhino