Sir Frederick Norton Kay Menzies (2 November 1875 – 14 May 1949) was a British physician and public health expert.

[1] He was born in Caernarvon on 2 November 1875, the son of Edith Madeline Kay and her husband, John Menzies, a civil engineer.

He then undertook postgraduate studies in both Berlin and Vienna returning to work at Edinburgh Royal Infirmary, receiving his doctorate (MD) in 1903.

[4][1] Menzies became principal assistant Medical Officer for Health, and part time public health consultant for London County Council's (LCC) responsible for the LCC scheme for the care of tuberculosis and for the diagnosis and care of venereal diseases in 1917.

Derek was a Major in the Royal Welch Fusiliers, and was recorded missing in action in Normandy on 10 June 1944.