Miriam Margolyes ( MAR-gə-leez; born 18 May 1941) is a British and Australian actress. Known for her work as a character actor across film, television, and stage, she received the BAFTA for Best Supporting Actress for her role as Mrs. Mingott in Martin Scorsese's The Age of Innocence (1993), and achieved international prominence with her portrayal of Professor Sprout in the Harry Potter film series (2001–2011). Margolyes was appointed Officer of the Order of the British Empire (OBE) in the 2002 New Year Honours for Services to Drama.

After starting her career in theatre, Margolyes made the transition to film with a small part in the British comedy A Nice Girl Like Me (1969). Subsequent credits include Yentl (1983), Little Shop of Horrors (1986), Little Dorrit (1988), I Love You to Death (1990), Immortal Beloved (1994), Balto (1995), Different for Girls, Romeo + Juliet (both 1996), Magnolia, End of Days (both 1999), Being Julia, and Ladies in Lavender (both 2004). She voiced roles in Babe (1995), James and the Giant Peach (1996), Mulan (1998), Happy Feet (2006), Flushed Away (2006), and Early Man (2018).

Margolyes appeared in the television films Poor Little Rich Girl: The Barbara Hutton Story (1987), Orpheus Descending (1990), Stalin (1992), Cold Comfort Farm (1995), and The Life and Death of Peter Sellers (2004). Her other credits include Blackadder (1983–1988), Vanity Fair, Supply & Demand (both 1998), and Doctor Who (2023), as well as the recurring roles of Prudence Stanley in the Australian drama series Miss Fisher's Murder Mysteries (2012–2015), and Sister Mildred in the BBC1 drama series Call the Midwife (2018–2021).

On stage, Margolyes toured her one-woman show, Dickens' Women, between 1989 and 2012, which earned her an Olivier Award nomination; starred as Sue Mengers in the Australian premiere of I'll Eat You Last (2014); and originated the role of Madame Morrible in Wicked (West End, 2006; Broadway, 2008).