Thomas Colby may refer to: Thomas Colby (MP for Melcombe Regis) (1530–1588), English politician Thomas Colby (MP for Thetford) (died 1588), MP for Thetford Sir Thomas Colby, 1st Baronet (1670–1729), MP for Rochester Thomas Frederick Colby (1784–1852), British major-general and director of the Ordnance Survey