Sir Sydney Philip Perigal Waterlow KCMG CBE (22 October 1878, New Barnet – 4 December 1944, Oare, Wiltshire) was a British diplomat, serving as British Minister to Thailand, Ethiopia and Bulgaria before he ended as Ambassador to Greece from 1933 to 1939.
He was educated at Eton and Trinity College, Cambridge, where he gained a first class in the Classics Tripos (B.A.
Resigning from the Foreign Office, Waterlow become a University extension lecturer until the outbreak of World War I, when he returned to the FO.
He rose to be Acting First Secretary in 1919, and participated in the Paris Peace Conference.
He was Envoy Extraordinary and Minister Plenipotentiary in Bangkok from 1924 to 1926, in Addis from 1928 to 1929, in Sofia from 1929 to 1933, and in Athens from 1933 to 1939.