William Henry Barlow FRS FRSE FICE MIMechE (10 May 1812 –12 November 1902) was an English civil engineer of the 19th century, particularly associated with railway engineering projects. Barlow was involved in many engineering enterprises. He was engineer for the Midland Railway on its London extension and designed the company's London terminus at St Pancras.With John Hawkshaw, he completed Isambard Kingdom Brunel's Clifton Suspension Bridge. Following the Tay Bridge disaster he sat on the commission which investigated the causes and designed the replacement Tay Bridge. Barlow was also an inventor and experimenter, patenting a design for a rail and carrying out investigations on the use and design of steel structures.