In association football, a League Cup or Secondary Cup generally signifies a cup competition for which entry is restricted only to teams in a particular league. The first national association football tournament to be called "League Cup" was held in Scotland in 1946–47 and was entitled the Scottish League Cup. However, in the Republic of Ireland the now defunct League of Ireland Shield was the first national league-only tournament of its kind; this was subsequently replaced by the League of Ireland Cup in 1973.

The creation of a League Cup marked the difference from the Association Cup or Primary Cup, which is generally also open to teams from multiple leagues, often as far down as regional amateur leagues, and who are also members of the country's football association.

The creation of a tournament of this kind exclusively for the top national-level league teams, in addition to the two main domestic association football tournaments of the league and association cup, also created a new national footballing achievement called the domestic "treble"; see Treble (association football). The first national league treble of this kind was won by Shamrock Rovers of the Republic of Ireland in 1925.

The Football League, also known as the npower Football League for sponsorship reasons, is a league competition featuring professional association football clubs from England and Wales. Founded in 1888, it is the oldest such competition in world football. It was the top level football league in England from its foundation in the 19th century until 1992, when the top 22 clubs split away to form the Premier League (reduced to 20 clubs in 1995).

The Football League has been associated with a title sponsor since 1983. As this sponsor has changed over the years the league has been known in turn as the Canon League, the Today League, the Barclays League, the Endsleigh League, the Nationwide Football League and the Coca-Cola Football League, until the present sponsor npower was adopted in 2010, contracted until 2013.

Since 1995 it has had 72 clubs evenly divided into three divisions, which are known as The Championship, League One, and League Two. Promotion and relegation between these divisions is a central feature of the League and is further extended to allow the top Championship clubs to exchange places with the lowest placed clubs in the Premier League, and the bottom clubs of League Two to switch with the top clubs of the Football Conference, thus integrating the League into the English football league system. Although primarily a competition for English clubs, one club from Wales also takes part, while in the past Swansea City, Wrexham, Newport County, Merthyr Town and Aberdare Athletic have been members.