Oliver St Clair or Sinclair may refer to:
Oliver St Clair, 12th Baron of Roslin (died 1523), Scottish noble Sir Oliver St Clair de Pitcairnis or Oliver Sinclair (died circa 1576), favourite courtier of James V of Scotland Olave Sinclair (died 1573), Scottish official in Orkney and Shetland Oliver Sinclair, character in Strike Back: Project Dawn