This chapter traces the history of the Scottish school of common-sense philosophy from c.1720 to 1828. It begins by examining the teaching of George Turnbull and his fellow regents at Marischal College, Aberdeen, in order to shed light on the early philosophical development of the so-called founder of the school, Thomas Reid. It next analyses the evolution of Reid’s critique of Humean scepticism and the theory of ideas in the years preceding the publication of his An Inquiry into the Human Mind, on the Principles of Common Sense (1764). Reid’s appeal to common sense is then compared and contrasted with those of James Beattie and James Oswald, whose writings, along with Reid’s Inquiry, were attacked by Joseph Priestley and other critics in the 1770s. Following a consideration of Reid’s response to Priestley in his Essays on the Intellectual Powers of Man (1785), the chapter discusses Dugald Stewart’s reformulation of Reid’s conception of common sense and his genealogy of the Scottish school of philosophy. Lastly it charts the collapse of the common-sense school around the time of Stewart’s death in 1828.