Jennifer Hennessy (born Jennifer Hayes in 1970) is an English actress. She has made numerous television appearances, including as Mrs.

Brazendale in the BBC TV series Lilies. Hennessy trained for three years at the Central School of Speech and Drama, graduating in 1992. She has since appeared in a number of theatrical roles, as well as on television, including the character of Jude in The Office; Julie, the man-hating shop-assistant, in the "Fockin Mokky Bokka" episode of Two Pints of Lager and a Packet of Crisps; and, in 2007, as Valerie Brannigan (the wife of Ardal O'Hanlon's character, Thomas Kincade Brannigan) in "Gridlock", an episode of Doctor Who, playing a vet in the BBC3 comedy "Pulling" (2008) and in the BBC mini-series South Riding in 2011.