Original Nike football shirt Celtic 2010/12

The Celtic Football Club is a professional football club in Glasgow, Scotland. The team competes in the Scottish Premiership, the top division of Scottish football. The club was founded in 1887 with the purpose of alleviating poverty in the Irish–Scots population in the city's East End area. They played their first match in May 1888, a friendly match against Rangers which Celtic won 5–2. Celtic established themselves within Scottish football, winning six successive league titles during the first decade of the 20th century. The club enjoyed their greatest successes during the 1960s and 70s under Jock Stein, when they won nine consecutive league titles and the 1967 European Cup. Celtic have played in green and white throughout their history, adopting in 1903 the hoops that have been used ever since.

Celtic are one of only five clubs in the world to have won over 100 trophies. The club has won the Scottish league championship 53 times, most recently in 2022–23, the Scottish Cup 41 times and the Scottish League Cup 21 times. The club's greatest season was 1966–67, when Celtic became the first British team to win the European Cup, also winning the Scottish league championship, the Scottish Cup, the League Cup and the Glasgow Cup. Celtic also reached the 1970 European Cup Final and the 2003 UEFA Cup Final, losing in both.

Celtic have a long-standing fierce rivalry with Rangers and, together, the clubs are known as the Old Firm. Their matches against each other are regarded as among the world's biggest football derbies. The club's fanbase was estimated in 2003 as being around 9 million worldwide and there are more than 160 Celtic supporters clubs in over 20 countries. An estimated 80,000 fans travelled to Seville for the 2003 UEFA Cup Final, and their "extraordinarily loyal and sporting behaviour" in spite of defeat earned the club Fair Play awards from FIFA and UEFA, respectively.