is an English professional footballer who plays as a midfielder for Women's Super League club Chelsea and the England women's national team. She is considered both a playmaker and a defensive midfielder. She has previously played for Blackburn Rovers, Manchester City, and Barcelona, and Great Britain at the Olympics. Walsh has numerous titles: she has won the Copa de la Reina once, and the Women's Super League; the Liga F; the FA Cup; the League Cup; the Supercopa de España; and the Champions League all on multiple occasions. With Manchester City and Chelsea she achieved one domestic treble each, while at Barcelona she successively achieved a continental treble and continental quadruple. She was part of the England team that won the Euro 2022, and was named player of the match in the final.

Walsh became a first team regular at City as a teenager during their 2014 campaign, playing a key role in helping the team secure their first League Cup. She stayed with the side for nine seasons (in eight years), briefly captaining them several times, and in March 2022 became the second player to reach 200 appearances for them; when she left to join Barcelona later that year, she jointly held City's record for number of appearances and set a world-record fee for a female footballer.

She represented England for their age-group teams from the age of twelve, helping the under-17 team to fourth in the 2014 U17 Euro and being named in its Team of the Tournament. She made her senior debut in 2017, for 2019 FIFA Women's World Cup qualifying, and started as captain in a match a year later. With England she has played in three major tournaments: the 2019 World Cup in which they placed fourth, the 2022 Euro that they won, and the 2023 World Cup that they finished as runner-up. With Great Britain, she competed at the 2020 Summer Olympics. She was named in the Team of the Tournament for the 2022 Euro, and is considered one of the best players and best midfielders in the world.