In 2009, Marquez appeared as Imogen Pollock in the made-for-TV movie Enid, detailing the life of children's writer Enid Blyton. Later in 2009, Marquez became the first child to win the British Comedy Award for 'Best Female Comedy Newcomer'. Outnumbered also won two other comedy awards on the night, including 'Best TV Comedy'. Marquez has also appeared in The King's Speech as Princess Margaret and Arthur Christmas as the voice of Gwen.
Marquez returned for the fifth series of Outnumbered. The show had not been broadcast for over two years and Ramona was only 10 years old when Series 4 was shown. The fifth series was shown on Wednesdays on BBC One starting on 29 January 2014.
In 2009, Marquez won the British Comedy Award for 'Best Female Comedy Newcomer', making her the youngest winner of a British Comedy Award in its 20-year history. She also shared two other awards with the cast and production team for Outnumbered at the same ceremony, including 'Best TV Comedy'.