Sister Ancilla Dent, OSB (born 3 June 1933) is an English Roman Catholic nun, ecological activist, and writer.
Born as Rosamond Mary Dent, she took the religious name of Sister Ancilla upon becoming a Benedictine nun. She was a nun at St Mildred's Abbey, Kent, England.
The elder daughter of William Herbert Shelley Dent and Mary Frances Katherine Petre, 19th Baroness Furnivall (b. 27 May 1900 - d. 24 December 1968), she and her younger sister, Patricia Mary Bence (b. 4 April 1935), are the descendents of Barons Furnivall. The barony has been in abeyance since 1968.