Guillermo Márquez is Dora's baby brother. He is a 1-year-old baby who has a twin sister named Isabella. He wears a blue shirt and a white diaper. In Happy Birthday, Super Babies he wears a different shirt and blue pants. He appeared in many episodes of Dora the Explorer starting with "Big Sister Dora". Like Isabella, he remained unnamed until the episode "Dora's Jack-in-the-Box", where his name was revealed. Like Isabella, he appears in the Dora and Friends episode "Magic Land", in which he appears a little older and can speak in full sentences. They also helped Dora in the Super Babies trilogy (Super Babies, The Super Babies Dream Adventure, and Happy Birthday, Super Babies!).
Appearances[]
Season 4[]
- Big Sister Dora (unnamed)
- Super Babies (unnamed)
- Catch the Babies (unnamed)
Season 5[]
- Dora's Jack-in-the-Box
- Bark, Bark to Play Park
- The Super Babies Dream Adventure
- Dora's Big Birthday Adventure
Season 6[]
Dora's Explorer Girls[]
Season 7[]
- A Ribbon For Pinto
- Dora's Easter Adventure
- Feliz Dia De Los Padres
- Dora & Diego's Amazing Animal Circus Adventure
- Baby Bongo's Big Music Show
- Dora's Thanksgiving Day Parade
Season 8[]
Go, Diego, Go![]
Dora and Friends: Into the City[]
- Magic Land!
- Buddy Race
- Magical Mermaid Adventure
- Dora's Rainforest Reunion
- Trick or Treat
- The Ballerina and the Troll Prince
- Kate and Quackers
Trivia[]
- In Dora and Friends: Into the City!, a slightly older Guillermo lives with his sisters, parents, and Abuéla in the city of Playa Verde.
- He and Isabella never appear individually (one of them appear and the other doesn't).