Lewis Cubitt (29 September 1799 – 9 June 1883) was an English civil engineer.
He was a younger brother of Thomas Cubitt, the leading master builder in London in the second quarter of the 19th century, and he designed many of the housing developments constructed by his sibling. He also was a younger brother of William Cubitt, the Lord Mayor of London.
He built many bridges in his career, most of them being in South America, Australia and India. Lewis was jointly responsible for designing the rebuilt London Bridge railway station in 1844. He also designed the King's Cross railway station, which was built in 1851–52, and the associated Great Northern Hotel, in 1854. As part of the ongoing redevelopment of the adjoining railway lands, now known as King's Cross Central, a granary by Cubitt is being refurbished for the art college Central Saint Martins, University of the Arts London.
He married Sophia Kendall (1811-1879) on 23 January 1830.