William Ellawala (born 1834) was a Ceylonese legislator. He was the Kandyan Sinhalese member of the Legislative Council of Ceylon. He was appointed to the post of Rate Mahatmaya by the British Government of Ceylon.
Born to Banda from Sabaragamuwa, he educated at the Ratnapura School and S. Thomas' College, Mutwal. He joined the government service in the Native Department and was appointed as a Rate Mahatmaya in 1856.
He married Jane Petronella Senanayake, daughter of Mudaliyar Don Bartholomew Senanayake. His daughter Agnes Ellawala married Mahawalatenne Rate Mahattaya of Balangoda and their daughters are Jane Mahawalatenne who married Abraham Obeyesekere Jayawardena of Kataluwa Walawwa and Rosalind Mahawatenne who married Barnes Ratwatte Dissawe. His great-granddaughter Sirimavo Bandaranaike became the first female prime minister in the world while his great great granddaughter Chandrika Bandaranaike became the first female Executive President of Sri Lanka. His niece Viollet Ellawala married John Hercules Meedeniya whose nephew Ranil Wickremesinghe became the President of Sri Lanka.