Sydney de Zoysa (1909 - October 20, 1994) was a Sri Lankan senior police officer. A former Deputy Inspector General of Police (DIG) of Range II and Permanent Secretary to the Ministry of Internal Security, he was one of co-conspirators of the attempted military coup of 1962.
Born to Sir Francis de Zoysa, KC an Advocate and member of the first State Council and Ethel Perera Amarasekera Siriwardena, his brother Stanly de Zoysa was a former Cabinet Minister of Finance and a Member of Parliament. His uncle was Sir A. E. de Silva. He was educated at Royal College, Colombo and at Ceylon University College where he read economics and was an active sportsmen.
While at university he joined the Ceylon Police Force as a Probationary Assistant Superintendent of Police and was sent to Tangalle District as his first duty station in 1937. He went on to become a Deputy Inspector-General of Police. He became the first Director of the Police Training School that was reestablished at Katukurunda, Kalutara in 1948. Prior to his retirement in 1959 he served as the DIG of Range II. After retirement he served as the Permanent Secretary to the Ministry of Internal Security.
During police serviced he received the Ceylon Police Medal for Meritorious Service, Defence Medal 1939-45, Ceylon Police Independence Medal and the Service Medal of the Order of St John.
As member of the Christian elite, who ever being deprived of the influence they once had due to the Sihinalaisation process started by Prime Minister S.W.R.D. Bandaranaike and carried on by Sirimavo Bandaranaike, several disgruntled christian officers of the army, navy and police began to plot a coup similar to that of General Ayub Khan. He was a co-conspirator of it and as been claimed to be the architect of it.