Inside jokes

In many Arthur productions and books, inside jokes have been seen or heard. These can include characters referencing to crew members or other inside information.

Season 2

D.W.'s Deer Friend

• During an imagine spot D.W. has about Walter the deer being homesick for his family when living with the Reads, among the relatives Walter lists off his his sister Sheilarae, most likely referencing to writer Sheilarae Carpentier Lau.

Season 4

What is that Thing?

• Muffy uses the bobbin to save a plush anteater of hers named "Artie" that wears Arthur's sweater.

That's a Baby Show!

• One of the names in the credits for Mary Moo Cow seen in the episode is Tolon Brown, Marc Brown's son.
• Another name in the credits for Mary Moo Cow is Alex Tankushev, which is probably a reference to storyboard artist Ivan Tankushev.

Season 7

Marc Brown can be seen at the far left of the row.

Elwood City Turns 100!

• Marc Brown is on the guest list and is seen sitting in the celebrity row.
• Jeremy O'Neill, an Arthur storyboard artist, was on the guest list

Season 12

Home Sweet Home

• Sanjeev and Irwin mention a teacher at their school named Mr. Fallon, referencing former writer on the show Joe Fallon.
• Sanjeev and Irwin also mention a teacher at their school named Mr. Scarborough, referencing writer Ken Scarborough.

Season 14

The Wheel Deal

• Sam Scarborough gets his name in this episode. The name is probably a reference to writer Ken Scarborough.

Season 15

The Trouble with Trophies

Marc Brown Certificate of Existence

• In Arthur's fantasy in the intro, Arthur is awarded the Marc Brown Certificate of Existence, referencing the fact that Marc Brown created Arthur.

Season 16

The car on the left has the license plate 9 Story.

The Last Tough Customer

• When Mrs. Bickles walks next to the ice cream shop, the car on the road's license plate is 9 Story. 9 Story Media Group started producing Arthur during that season.

Baseball Blues

• In the opening, Wally is seen using a microphone that has "WGBH" written on it. WGBH produces many PBS and PBS Kids programs, including Arthur.

Season 20

Marc Brown at Fern's book signing.

Fern's Flights of Fancy

• Marc Brown is seen at Fern's book signing. He asks her to make his book out to him.

Season 23

D.W. and Dr. Whosit

One of the passwords shown in the password book is "Ar1976." The first Arthur book was published in 1976.

Arthur - It's Only Rock 'n' Roll

• D.W. dismisses liking Crazy Bus entirely, saying that it is for little kids. This is a reference to the writer and performer of the song, Joe Fallon, leaving the show.

Arthur Books

• In the Arthur Adventure series, Marc Brown hid the names of his children, Tolon, Tucker, and Eliza, in illustrations on each page. These are also present in some spinoff titles.
• In Arthur's Tooth, the spelling words on Mr. Marco's blackboard reference previous Arthur books, such as "Santa," "eyes," and "camp."