Galagama Sri Aththadassi Thera (11 January 1922 – 9 March 2016) was a Sri Lankan Buddhist monk who served as the 21st Mahanayaka of the Asgiriya Chapter of Siyam Nikaya. He was appointed on 8 May 2015 following the death of Chief Prelate Most Venerable Udugama Sri Buddharakkitha Thero on 8 April 2015.
The Venerable Thera died aged 94 while receiving treatment at the Intensive Care Unit of the Kandy Hospital. He was hospitalized while in an unconscious state after a fall.