Oswald Rayner (29 November 1888, in Smethwick, Staffordshire, England – 6 March 1961, in Botley, Oxfordshire, England) was a British MI6 agent in Russia during World War I.
He is believed by some to have been involved in the final murder plot against Grigori Rasputin, but "the archives of the British intelligence service (MI6) do not hold a single document linking Rayner, Hoare, or any other British agent or diplomat to the murder."