Teresa Gallagher is an American-born British voice actress for The Amazing World of Gumball. She is the voice of Nicole, Penny, Mrs. Robinson, Jackie, Teri, Polly, Ms. Markham, Siciliana, Chi Chi's mother, Felicity (in "The Kids"), Carmen (in season 1), and the book doctor.
- Lapitch the Little Shoemaker (Lapitch, Perwinkle Percival III)
- Mama Mirabelle's Home Movies (Karla the Zebra, 2007–2017)
- The Pinky and Perky Show (KT, 2008–2009)
- Thomas & Friends (Rosie; formerly, Emily, Mavis, Belle, Lady Hatt, Annie, and Clarabel, 2009-present)
- Alphablocks (Various)
- The Amazing World of Gumball (Nicole Watterson, Penny Fitzgerald, Teri, Jackie Wilson, Margaret Robinson, Polly Fitzgerald, Siciliana Pepperoni, Ms. Markham, Chi Chi's mother, Charlie-Ann, Felicity Parham ("The Kids" only), Carmen (season 1 only), the book doctor, 2011–present)
- Thunderbirds Are Go (EOS and various other female characters, 2015–present)
- Teletubbies (Voice Trumpets, Tiddlytubbies, 2015–present)
- Miffy's Adventures Big and Small (2015–present)
- While she does put up a great American accent in her role, Gallagher's native accent has slipped twice in "The Gi," "The Mothers," once in "The Job," and various other times, usually when she says the word "anything."
- She voices the titular protagonist of Disney Junior's Henry Hugglemonster (in the UK) with her usual British accent.
- She, Kerry Shale, and Rupert Degas have provided voices for the British television show, Thomas & Friends.