Ada Cambridge (21 November 1844 – 19 July 1926), later known as Ada Cross, was an English-born Australian writer. She wrote more than twenty-five works of fiction, three volumes of poetry and two autobiographical works. Many of her novels were serialized in Australian newspapers, and were never published in book form. While she was known to friends and family by her married name, Ada Cross, she was known to her newspaper readers as A.C.. Later in her career she reverted to her maiden name, Ada Cambridge, and it is thus by this name that she is known.