Stephen Adam Amell (born May 8, 1981) is a Canadian actor. He came to prominence for playing the lead role of Oliver Queen on the CW superhero series Arrow (2012–2020), based on DC Comics. Amell also appeared in subsequent Arrowverse franchise media, along with reprising his role in various video games. Following the conclusion of Arrow, Amell landed the lead roles in both the Starz drama series Heels (2021–2023), and Suits LA, the sequel to Suits.

Outside of television, Amell portrayed Casey Jones in the superhero film Teenage Mutant Ninja Turtles: Out of the Shadows (2016). He co-produced and starred in Code 8 and its sequel Code 8: Part II with his cousin Robbie Amell. He has also made a number of appearances in the professional wrestling circuit.

Stephen Adam Amell was born on May 8, 1981, in Toronto, Ontario, the son of Sandra Anne (née Bolté) and Thomas J. Amell. He is a first cousin of actor Robbie Amell. He attended St. Andrew's College, a private independent school for boys, and graduated in 2000.

Amell appeared in two episodes of the fourth season of Queer as Folk as the Liberty Ride spinning instructor in 2004. Amell played Adam in the first season of the television series Dante's Cove; he was replaced in the second season by Jon Fleming. In 2007, Amell won a Gemini Award for his guest-starring role on ReGenesis. The same year he was also nominated for a Gemini Award in the Best Ensemble Cast Category for Rent-a-Goalie. He had recurring roles in the TV series Da Kink in My Hair and Heartland. On December 3, 2010, Amell joined the cast of The Vampire Diaries as werewolf 'Brady' for season 2. Amell starred as the real life convicted killer Joran van der Sloot in the Lifetime film Justice for Natalee Holloway which originally aired in May 2011.

On October 2, 2011, season 3 of HBO's series Hung premiered with Amell starring as busboy-turned-prostitute Jason, a younger rival "ho" to Thomas Jane's Ray Drecker. He also appeared as Jim in the fourth season of 90210. Amell announced on October 28, 2011, that he had just finished filming the Christmas episode of New Girl with Zooey Deschanel and Max Greenfield. He touches on the experience of filming his first "network half-hour comedy" in an interview with Daemon's TV. On November 9, 2011, Amell was announced for the recurring role of Scottie, a paramedic on ABC's Private Practice. He also played the role of Travis McKenna in Blue Mountain State.

In January 2012, Amell was cast as Oliver Queen in The CW series Arrow, based on the DC Comics superhero of the same name. This series and role led to Amell appearing as the character on other superhero series on the network as part of the growing Arrowverse, including The Flash, Legends of Tomorrow, Supergirl, and Batwoman, as well as the CW Seed webseries Vixen.

Amell co-starred in Teenage Mutant Ninja Turtles: Out of the Shadows (released on June 3, 2016) as vigilante "Casey Jones". Amell announced in May 2017 that he would be participating on a special celebrity edition of American Ninja Warrior. Amell demonstrated great physical abilities which was reflective of his athleticism in his portrayal of Oliver Queen. In 2017, he took part in the directorial debut of former Heartland co-star Michelle Morgan, a short film entitled Mi Madre, My Father, playing the estranged father of a six-year-old girl. Morgan raised funds for the production through a crowdfunding campaign. The film premiered at the 2018 Cannes Film Festival.

In March 2019, Amell announced the end of Arrow with its eighth and final season, which premiered in October 2019 and concluded in January 2020.