Alison Pill (born November 27, 1985) is a Canadian actress. A former child actress, she began her career at age 12, appearing in numerous projects before transitioning to adult roles with a breakthrough role in the television series The Book of Daniel (2006), a tv series on NBC. Also in 2006, she made her Broadway debut in The Lieutenant of Inishmore (2006) earning a nomination for Tony Award for Best Featured Actress in a Play. Pill's other notable stage roles include being in Blackbird (2007), Mauritius (2007), The Miracle Worker (2010), The House of Blue Leaves (2011), and Three Tall Women (2018).

Pill had prominent roles in the films Confessions of a Teenage Drama Queen (2004), Plain Truth (2004), Dan in Real Life (2007), Milk (2008), Midnight in Paris (2011), Hail, Caesar! (2016), and Vice (2018). From 2012 to 2014 she played Maggie Jordan in Aaron Sorkin's HBO drama series The Newsroom and acted in the television series In Treatment (2009), The Pillars of the Earth (2010), American Horror Story: Cult (2017), Star Trek: Picard (2020–2022), Devs (2020), and Them (2021). She is also known for her role as Kim Pine in the film Scott Pilgrim vs. the World (2010) and the Netflix animated series Scott Pilgrim Takes Off (2023).

Pill was born in Toronto. Her father, a professional engineer, is Estonian. She attended Vaughan Road Academy in the city. She was in its Interact program which featured dance, music, athletics, and theater.

Pill decided to become an actor when she was 10 years old. As a member of the Toronto Children's Chorus, she was chosen to narrate one of their performances. Her mother tried to discourage Pill by getting her a job as a background performer on the series Kung Fu: The Legend Continues. By the time she was 11, she had played a guest role on an episode of the children's series The New Ghostwriter Mysteries. At 12, she landed roles in two TV movies and a mini-series, a guest appearance on the TV series Psi Factor and voiced the character "Cornflower" on the animated series Redwall (1999–2001). After roles in two more television movies, she landed her first feature film role, a small-budget Canadian movie called The Life Before This in 1999, followed by the role of Jacob's older sister Marfa in Jacob Two Two Meets the Hooded Fang, another Canadian movie. Pill played roles in four more TV movies before the age of fourteen. She landed a small role in Skipped Parts in 2000 starring Drew Barrymore and Mischa Barton, then appeared in four more TV movies and features that year, including playing Farrah Fawcett's daughter in the TNT movie Baby and a lead role in the Canadian film The Dinosaur Hunter, which was originally intended to be shown at a dinosaur museum and on a provincial education channel, but which made its way to the Burbank International Film Festival, winning Pill an award for Best Child Actress.

She landed the role of young Lorna in the ABC-TV biopic Life with Judy Garland: Me and My Shadows in 2001, based on the memoir by Garland's daughter, Lorna Luft. Also in 2001, Pill also played Sissy Spacek's daughter in the TV flick Midwives. In 2003, she played Katie Holmes' sister in the indie feature Pieces of April. Pill won the lead in the CTV-TV movie Fast Food High, about a teenager who gets a job at a fast food restaurant and tries to set up a union. She also landed a supporting role in Confessions of a Teenage Drama Queen in 2003, starring Lindsay Lohan. Pill ventured into stage acting, with the Manhattan, New York staging of None of the Above as the first item in her theater credentials. In 2006, she starred as Grace Webster in the short-lived NBC drama The Book of Daniel. That same year, she made her Broadway debut playing Mairead in Martin McDonagh's black comedy play The Lieutenant of Inishmore for which she was nominated for the Tony Award for Best Featured Actress in a Play.

Because of her busy work schedule, Pill's schooling was through a program for children in the entertainment industry. Since graduating from high school, she moved to New York to pursue a career in theatre, but continued to work in movies such as Dan in Real Life in 2007. She returned to Broadway in the Theresa Rebeck play Mauritius (2007) acting alongside F. Murray Abraham, Bobby Cannavale, and Dylan Baker. John Lahr of The New Yorker commended Pill as "excellent" adding, "It says something about the appeal of Alison Pill—an actress with a big future—that her compelling combination of ferocity and fragility carries the audience beyond the inconsistencies of the story." In 2007, she acted in the Manhattan Theatre Club production of the David Harrower play Blackbird starring alongside Jeff Daniels. The production was directed by Joe Mantello and was helmed at Center's Stage I in Manhattan, New York. For her performance she received the Drama League Award, Lucille Lortel Award, and Outer Critics Circle Awards nominations. That was followed by The Distance From Here, On the Mountain,.

Pill had a major supporting role as campaign manager Anne Kronenberg in the 2008 film Milk. In 2009, she performed with Erin Hill & her Psychedelic Harp playing the Twilight Zone-inspired "Meredith Moon" and "The Real North Pole" sci-fi Christmas Harp. Pill was cast as April on In Treatment. In 2009 she replaced Elliot Page in a role in Jack & Diane but due to postponement of the project neither ended up in it by the time it ran in 2012. Pill later played Kim Pine in the movie Scott Pilgrim vs. the World (2010) as well as in the short, Scott Pilgrim vs. the Animation. She portrayed Empress Maud in the miniseries The Pillars of the Earth.

Pill starred with Abigail Breslin in the Broadway revival of the William Gibson play The Miracle Worker (2010), David Rooney of Variety wrote, "Pill has demonstrated her skill at animating prickly contemporary women who can go from sullen vulnerability into bellicose attack mode in a flash. She's no less convincing as 20-year-old Boston Irish Sullivan, hired in 1887 by the Keller family in Alabama to serve as governess to Helen, left deaf and blind by an illness in her infancy". In 2011, she acted in another Broadway revival, the John Guare play The House of Blue Leaves with Ben Stiller, Edie Falco, Jennifer Jason Leigh, and Thomas Sadoski. In the play she portrayed a kindly, partially deaf actress. She received positive reviews with Entertainment Weekly describing her as "delightfully daffy", and The Hollywood Reporter declaring, "Pill's funny-sad ethereal performance exposes the cultivated poise and glamour of Hollywood as another empty fantasy". She appeared in Woody Allen's acclaimed romantic comedy Midnight in Paris (2011) portraying Zelda Fitzgerald alongside Tom Hiddleston as F. Scott Fitzgerald. In 2012, she reunited with Allen portraying Hayley in To Rome with Love (2012). She starred in short films including Denise in 2012 with Chris Messina and Santa Baby; she also sang and danced in Santa Baby. In 2016, she appeared in Cover Up by Satya Bhabha with Jason Ritter, to be released at the LA Shorts Fest, and Woman in Deep, playing a woman who calls a suicide prevention hot line and is put on hold, directed by Janicza Bravo.