This article focuses on unpublished manuscript notes by Lord William Wyndham Grenville on the first edition of David Ricardo’s On the Principles of Political Economy. Its aim is twofold. First, it is to strengthen our knowledge of Grenville’s economic thought which was praised by figures of his time but remains today almost totally unrecognised. The second purpose is to assess the part that Grenville may have taken in the development of Post-Ricardian political economy. Our conclusion is that Grenville most likely played a key role in the development of Political economy at the University of Oxford in the late 1820 s and early 1830 s.