Jonathan Lee Miller (born 15 November 1972) is an English actor. He achieved early success for his portrayal of Simon "Sick Boy" Williamson in the dark comedy-drama film Trainspotting (1996) and as Dade Murphy in Hackers (1995) before earning further critical recognition for his performances in Afterglow (1997), Mansfield Park (1999), Mindhunters (2004),The Flying Scotsman (2006), Endgame (2009), and T2 Trainspotting (2017). For The Flying Scotsman he received a London Film Critics' Circle nomination for Actor of the Year. He was also part of the principal cast in the films Melinda and Melinda (2004), Dark Shadows (2012), and Byzantium (2013). He has appeared in several theatrical productions, most notably After Miss Julie and Frankenstein, the latter of which earned him an Olivier Award for Best Actor.

Miller starred as the title character in the ABC comedy drama Eli Stone, for which he received a Satellite Award nomination for Best Actor. This was followed by another starring role in the BBC costume drama Emma and a supporting role as Jordan Chase in the fifth season of the Showtime drama Dexter. From 2012 to 2019 he starred as a modern-day version of Sherlock Holmes in the CBS crime drama Elementary, which earned him his second Satellite Award nomination for Best Actor. In 2022, he played British prime minister John Major in the fifth season of the Netflix historical drama The Crown.