Dame Mary Monica Cunliffe-Owen, Mrs Wills DStJ (18 January 1861 – 2 April 1931) was an English philanthropist.
She was born in Brompton, Middlesex, the daughter of Sir Philip Cunliffe-Owen and Jenny Eliza Pamila Julia (von Reitzenstein). In 1886, she married Henry Herbert Wills, a member of the Wills tobacco family; the union was apparently childless. She spent her latter years at Rockdunder, Wrington, Somerset, and it was there that she died on 2 April 1931. Her sister, Victoria Mary Louise Adelaide Cunliffe-Owen, was married to the publisher Otto Kyllmann.