|3rd Grade Male Rat|
|Cartoon debut||Arthur's Eyes|
"3rd Grade Male Rat" is an unnamed third grader in Miss Sweetwater's class.
He played the flute for the school band in "Elwood City Turns 100!".
He makes regular appearances in many episodes. He appears to get along with other kids. His only line occurs while he is walking past Buster, Arthur, and Binky in the episode "Buster's Growing Grudge".
3rd Grade Male Rat is a rat with an olive green complexion. He has whiskers and a little hair. He wears a blue-and-white striped pullover and brown pants with blue sneakers. His backpack is green. In the episode Germophobia he wore light blue swim trunks.
In Buster's Growing Grudge, he was shown walking up the steps mumbling, "Oh, Dear. Oh Dear." He may have been having a bad day or an overall nervous and pessimistic personality. Not much is known about him, but he appears to be nice and friendly to the other kids.
- Muffy Crosswire: She invited him to her spring party.
- 3rd Grade Male Cat: Seen walking out of the movie theater together in The Agent of Change.
- Season 1
- Season 2
- Arthur's Lucky Pencil 20202
- Buster and the Daredevils 20302
- Buster Baxter, Cat Saver 20601
- Arthur's TV-Free Week 20701
- Arthur vs. the Piano 20801
- Arthur's Mystery Envelope 21002
- Buster Hits the Books 21102
- Arthur and the Square Dance 21202
- Water and the Brain 21301
- Love Notes for Muffy 21601
- D.W. Blows the Whistle 21602
- Season 3
- The Ballad of Buster Baxter 30102
- Revenge of the Chip 30502
- Meet Binky 30602
- Arthur Rides the Bandwagon 30701
- Dad's Dessert Dilemma 30702
- Buster's Growing Grudge 30802
- Arthur's Almost Live Not Real Music Festival 31102
- What Scared Sue Ellen? 31201
- Arthur's Dummy Disaster 31301
- Arthur and D.W. Clean Up 31501
- The Long, Dull Winter 31502
- Season 4
- Season 5
- Season 6
- Season 7
- Season 8
- Season 9
- Season 10
- Season 11
- Season 12
- The Cherry Tree 120601
- Season 13
- Season 14
- Season 15
- Season 16
- Season 20
- According to "Sue Ellen Moves In", Buster thinks he is an alien.
- In "Francine's Big Top Trouble", Arthur imagines D.W. being respected by everyone because she is his little sister. 3rd Grade Male Rat was shown cheering D.W. on in front of Lakewood Elementary School with other students.
- He may have some sort of food allergy or restriction as he was seen at the special foods table in "Binky Goes Nuts". However, he may have just been sitting with a friend.