Sinnakutty Odayar Canagaratnam (; 1880 – May 1938) was a Ceylon Tamil civil servant, politician and member of the State Council of Ceylon.
Canagaratnam was born in 1880. He was the son of Sinnakutty Odayar from Karaitivu in south-eastern Ceylon. He was educated at St. Andrew's English School, Batticaloa.
Canagaratnam was married to Muththamma, daughter of J. Abraham. They had four daughters - Daisy, Grace, Carmaline and Violet.
Canagaratnam joined the Government Clerical Service and was later appointed Deputy Fiscal for Batticaloa District and Chief Mudaliyar for the Eastern Province. After retirement Canagaratnam contested the 1936 state council election as a candidate for the Batticaloa South seat and was elected to the State Council of Ceylon. receiving 14,021 votes polled, against K.M. Abdul Majeed's 8,216 votes and the third placed M.A.L.Kariapper's 1,557 votes.
In 1921 Canagaratnam wrote a monograph, Monograph of the Batticaloa District of the Eastern Province, Ceylon. He died in May 1938.