Diwan Bahadur Sir Thyagaraja Sadasiva Iyer M.A., B.L., (23 June 1861 – 1 December 1927) was an Indian judge and theosophist who served as the Chief Justice of Travancore from 1905 to 1910. He was also the first President of the Hindu Religious and Charitable Endowments Department (HR & CE), Madras Presidency.