Rangers Football Club is a Scottish professional football club based in the Govan district of Glasgow which plays in the Scottish Premiership. Although not its official name, it is often referred to as Glasgow Rangers outside Scotland. The fourth-oldest football club in Scotland, Rangers was founded by four teenage boys as they walked through West End Park (now Kelvingrove Park) in March 1872 where they discussed the idea of forming a football club, and played its first match against the now defunct Callander at the Fleshers' Haugh area of Glasgow Green in May of the same year. Rangers' home ground, Ibrox Stadium, designed by stadium architect Archibald Leitch and opened in 1929, is a Category B listed building and the third-largest football stadium in Scotland. The club has always played in royal blue shirts.

Rangers is the most successful club in Scottish football. The club has won the Scottish League title a record 55 times, the Scottish Cup 34 times, the Scottish League Cup a record 27 times and the domestic treble on seven occasions, a joint world record shared with rivals Celtic. Rangers won the European Cup Winners' Cup in 1972 after being losing finalists twice, in 1961 (the first British club to reach a UEFA tournament final) and 1967. The club has lost a further two European finals; they reached the UEFA Cup Final in 2008 and a fourth runners-up finish in European competition came in the UEFA Europa League Final in 2022.

Rangers has a long-standing rivalry with Celtic, the two Glasgow clubs being collectively known as the Old Firm, which is considered one of the world's biggest football derbies. With more than 600 Rangers supporters' clubs in 35 countries worldwide, Rangers has one of the largest fanbases in world football. The club holds the record for the largest travelling support in football history, when an estimated 200,000 Rangers fans arrived in the city of Manchester for the 2008 UEFA Cup Final. Rangers also took the largest ever travelling support abroad when an estimated 100,000 fans arrived in Seville for the 2022 UEFA Europa League Final.

One of the 11 original members of the Scottish Football League, Rangers remained in the top division continuously until a financial crisis during the 2011–12 season saw the club enter administration and the original company liquidated with the assets moved to a new company structure. The club was accepted as an associate member of the Scottish Football League and placed in the fourth tier of the Scottish football league system in time for the start of the following season. Rangers then won three promotions in four years, returning to the Premiership for the start of the 2016–17 season. While in the Scottish lower divisions, Rangers became the only club in Scotland to have won every domestic trophy. In 2020–21, Rangers won the Scottish Premiership, their first Scottish championship in ten years, a then world record fifty-fifth league win. It also stopped rivals Celtic in their quest to break the domestic record by winning ten titles in a row.