Davy Klaassen (born 21 February 1993) is a Dutch professional footballer who plays as an attacking midfielder for Eredivisie club Ajax and the Netherlands national team.

[3] Klaassen began his football career in the youth ranks of local amateur side HVV de Zebra's, where he played until 2003, when he transferred to HSV Wasmeer.

[5] Klaassen made his debut for the first team in the UEFA Champions League group stage away draw (0–0) against Olympique Lyonnais on 22 November 2011 replacing Lorenzo Ebecilio in the 85th minute.

[12] Following the departure of Ajax captain Siem de Jong, Klaassen switched to the vacant number 10 shirt for the upcoming season.

[15] He made his first official appearance for Everton in a 1–0 win over MFK Ružomberok in the UEFA Europa League third qualifying round first leg.

[16] Klaassen made his league debut for Everton on 12 August 2017, when his club beat Stoke City 1–0 at Goodison Park.

[17] Klaassen endured a difficult season with the club, falling out of favor with both Sam Allardyce and Marco Silva after Ronald Koeman was fired in October 2017.

[24] In the relegation play-off that season, Klaassen played an important role in helping Werder Bremen secure their Bundesliga status by captaining the team in a 2-2 draw with Heidenheim.

On 5 April 2023, during a Dutch cup semifinal away against Feyenoord, he suffered a head injury when he was hit by an object thrown from the stands.

[36] On 22 September 2009, Klaassen made his first appearance for the Netherlands U17 team in a friendly encounter against France U17 which ended in a 1–0 loss for the Dutch.

In his 7th appearance for the under-19 side he scored both his first and second goal on 10 November 2011 in a qualification match ahead of the 2012 UEFA European Under-19 Championship against Moldova U19 with the Netherlands failing to qualify for the final tournament in Estonia.

[38] Due to injuries sustained by Ruben Ligeon, Yassin Ayoub and Jürgen Locadia for the Netherlands U21 selection, Klaassen received his first call-up for Jong Oranje the under-21 selection of the Netherlands as a replacement along with Thomas Bruns and Timo Letschert for the 2015 UEFA European Under-21 Football Championship qualification match against Georgia U21, as well as the friendly match against Austria U21 four days later.

[44] He appeared as a second-half substitute in a friendly draw with Spain,[45] before starting in UEFA Nations League fixtures against Bosnia & Herzegovina[46] and Poland.