Sir Thomas John Parker, GBE, FREng, HonFIES, HonFIET (born 8 April 1942) is a British businessman. He is chairman of Laing O'Rourke and former chairman of Pennon Group, a director of Carnival Corporation & plc and lead non-executive director at the Cabinet Office. He has been a director or chairman of numerous other public companies including Airbus, Anglo American plc, Babcock International, British Gas, DP World, Lattice Group, National Grid plc and Ombu Group. He is a past President of the Royal Academy of Engineering, patron at the Centre for Process Innovation and a Visiting Fellow of the University of Oxford.