Sir Ian Murray McKellen (born 25 May 1939) is an English actor. He has played roles on the screen and stage in genres ranging from Shakespearean dramas and modern theatre to popular fantasy and science fiction. He is regarded as a British cultural icon and was knighted by Queen Elizabeth II in 1991. He has received numerous accolades, including a Tony Award, six Olivier Awards, and a Golden Globe Award, and he has been nominated for two Academy Awards, five BAFTA Awards, and five Emmy Awards.

McKellen made his stage debut in 1961 at the Belgrade Theatre as a member of its repertory company and, in 1965, made his first West End appearance. In 1969, he was invited to join the Prospect Theatre Company to play the lead parts in Shakespeare's Richard II and Marlowe's Edward II. In the 1970s, McKellen became a stalwart of the Royal Shakespeare Company and the National Theatre of Great Britain. He has earned five Olivier Awards for his roles in Pillars of the Community (1977), The Alchemist (1978), Bent (1979), Wild Honey (1984), and Richard III (1995). McKellen made his Broadway debut in The Promise (1965). He received the Tony Award for Best Actor in a Play for his role as Antonio Salieri in Amadeus (1980). He was further nominated for Ian McKellen: Acting Shakespeare (1984). He returned to Broadway in Wild Honey (1986), Dance of Death (1990), No Man's Land (2013), and Waiting for Godot (2013), the latter two being a joint production with Patrick Stewart.

McKellen achieved worldwide fame for his film roles, including the titular King in Richard III (1995), James Whale in Gods and Monsters (1998), Magneto in the X-Men films, Cogsworth in Beauty and the Beast (2017) and Gandalf in The Lord of the Rings (2001–2003) and The Hobbit (2012–2014) trilogies. Other notable film roles include A Touch of Love (1969), Plenty (1985), Six Degrees of Separation (1993), Restoration (1995), Mr. Holmes (2015), and The Good Liar (2019).

McKellen came out as gay in 1988 and has since championed LGBT social movements worldwide. He was awarded the Freedom of the City of London in October 2014. McKellen co-founded Stonewall, an LGBT rights lobby group in the United Kingdom named after the Stonewall riots. He also patronises LGBT History Month, Pride London, Oxford Pride, GayGlos, LGBT Foundation and FFLAG.