He is an only child whose parents divorced when he was young. He has asthma, is obsessed with aliens, loves telling jokes, is an amateur detective, practices gardening, and plays the tuba. He loves eating and keeps expired food in his room and school desk. He is a white rabbit who wears a turquoise long-sleeve polo shirt and jeans. Buster Baxter (voiced by Daniel Brochu Jonathan Morris 2002–2012, 2000 redub, under-credited as Conway Bruce) is Arthur's best friend.However, she comes to understand her family's speech better. As she grows up, she loses communication with some of these characters. She can communicate with animals such as Pal, Mei-Lin Barnes, Killer, Toady, Mr. Kate Read (voiced by Tracy Braunstein) is Arthur and D.W.'s baby sister.It is also confirmed in the episode 'Arthur's First Day' that she hates the name Dora Winifred. When she is introduced as an adult in the series finale 'All Grown Up', it is confirmed that she has taken up the profession of law enforcement. is inspired by his own experiences with his own three little sisters (especially Kim Brown). She can be bossy, selfish, arrogant, spiteful, and often downright wrathful, especially towards her brother.

was named after Grandma Thora's aunt Dora Winifred, who died before she was born. In the special episode 'The Rhythm and Roots of Arthur', it is revealed that D.W. is fully literate and reads complex material in several episodes.

She attends preschool and enjoys watching the TV show 'Mary Moo Cow' and listening to the song 'Crazy Bus', much to Arthur's annoyance.

Dora Winifred Read (usually known as D.W.) (voiced by Michael Caloz 1996–1999 Oliver Grainger 1999–2001 Jason Szwimer 2002–2006 Mariella Miller 2002–2012 Luciano Rauso 2006 Ryan Ehrenworth 2007 Robert Naylor 2007–2012 Jake Beale 2012–2014 Andrew Dayton 2014–2016 Christian Distefano 2016–2018 Ethan Pugiotto 2019–2022 Nissae Isen 2022) is a four (later five)-year-old, brown-haired, middle child of the Read family who usually wears a long-sleeve white blouse underneath a sleeveless, knee-length, pink jumper dress.

He plays the piano, wears a yellow sweater with a white collared shirt underneath, blue jeans, and round brown glasses.

Arthur Timothy Read (voiced by Michael Yarmush 1996–2000, 2022 Justin Bradley 2001 Mark Rendall 2002–2003, 2001 redub Kye Sones 2002–2012, 2001 redub Cameron Ansell 2004–2007 Dallas Jokic 2008–2012 Drew Adkins 2012–2014 William Healy 2014–2016 Jacob Ursomarzo 2016–2018 Roman Lutterotti 2019–2022) is an eight-year-old aardvark who attends third grade at Lakewood Elementary in Elwood City.

Buster Changes His Luck by Marc Brown