William Strahan (24 March 1715 – 9 July 1785) was a Scottish printer and publisher, and a Member of Parliament.
Born in Edinburgh as William Strachan, and educated at the Royal High School, Strahan was originally apprenticed to an Edinburgh printer but became a Master Printer in London (at which time he changed the spelling of his name). In 1738 he was made a Freeman of the City of London and a freeman of the Stationers' Company. He married Margaret Penelope Elphinstone, daughter of Edinburgh Episcopal Clergyman William Elphnstone, at St Mary Le Bow on 20 July 1738. They had five children, two daughters and three sons, one of whom, Andrew, would succeed him as King's Printer.
Diversifying from printing to publishing, he built up a highly important and successful business, at one time employing 50 men. He was Samuel Johnson's chief publisher, being entrusted with the printing of Johnson's Dictionary, and also published the works of the philosophers David Hume and Adam Smith, and the historian Edward Gibbon. Prominent 18th Century Freemason William Preston had attended the same school as Strahan in Edinburgh and was employed by Strahan, as an editor, particularly of David Hume's works. From 1770, Strahan was Printer to the King. Strahan was also the printer for the successful London bookseller Andrew Millar, as well as his longtime friend and business partner. Between 1740–65 Strahan moved his London premises four times in the area between St Bride’s and the Strand. By 1770 he owned the biggest printing operation in the kingdom, comprising three separate printing businesses in six buildings.