Katherine Parkinson (born 9 March 1978) is an English actress. She appeared in the Channel 4 comedy series The IT Crowd as Jen Barber, for which she won the British Comedy Award for Best Television Actress in 2009 and 2014 and was twice nominated for the BAFTA Television Award for Best Female Comedy Performance, winning in 2014.

Parkinson trained at the London Academy of Music and Dramatic Art and has performed on stage in The Seagull (2007), Cock (2009) and Home, I'm Darling (2018), for which she was nominated for the Laurence Olivier Award for Best Actress in a Play.

Parkinson was also one of the main cast members of the series Doc Martin for three seasons (2005–2009). She appeared in all three seasons of the science fiction drama Humans on AMC/Channel 4, which aired from 2015 to 2018. She also appeared in the films The Boat That Rocked (2009) and The Guernsey Literary and Potato Peel Pie Society (2018).