St Giles' Cathedral, or the High Kirk of Edinburgh, is a parish church of the Church of Scotland in the Old Town of Edinburgh. The current building was begun in the 14th century and extended until the early 16th century; significant alterations were undertaken in the 19th and 20th centuries, including the addition of the Thistle Chapel. St Giles' is closely associated with many events and figures in Scottish history, including John Knox, who served as the church's minister after the Scottish Reformation.

The Church of Scotland is a Presbyterian denomination of Christianity that holds the status of the national church in Scotland. It is one of the country's largest, having 259,200 members in 2023. While active membership in the church has declined significantly in recent decades, the government Scottish Household Survey found that 20% of the Scottish population, or over one million people, identified the Church of Scotland as their religious identity in 2019. The Church of Scotland's governing system is presbyterian in its approach, therefore, no one individual or group within the church has more or less influence over church matters. There is no one person who acts as the head of faith, as the church believes that role is the "Lord God's". As a proper noun, the Kirk is an informal name for the Church of Scotland used in the media and by the church itself.