Sadasivan is a surname and a given name. Notable people with the name include:
Given name: Sadasivan KM Nambisan, aka Sadu, Indi-pop singer, composer, lyricist and producer Sadasivan Radhakrishnan PVSM, AVSM, retired officer in the Indian Air Force
Surname: Ayiroor Sadasivan (1939–2015), Indian playback singer mainly in Malayalam cinema Balaji Sadasivan (1955–2010), Singaporean politician and neurosurgeon C. K. Sadasivan (born 1953), Indian politician, former member of the Kerala Legislative Assembly Rahul Sadasivan, Indian filmmaker and screenwriter in Malayalam cinema S. N. Sadasivan (1926–2006), Indian author Toppur Seethapathy Sadasivan (1913–2001), Indian plant pathologist in the University of Madras Viswa Sadasivan (born 1959), Nominated Member of Parliament in the Parliament of Singapore