The history of sectarianism in Scotland is most commonly associated with conflict and prejudices between religions, and especially Catholic and Protestant groups.

The Reformation movement of the 15th century saw Protestantism, a new 'sect' - or denomination of Christianity - sweep across western Europe. There was considerable public support for this movement in Scotland, which had previously been a predominantly Catholic country. Protestantism was later adopted by the state as Scotland's national religion.

The 17th and 18th century saw conflict between the Jacobite followers of Catholic King James VII and the forces of King William and Queen Mary, who took the throne in 1688 and were Protestants. In the 19th century the prospect of Jacobite invasion declined yet sectarian conflict continued as a result of immigration by those who fled famine in Ireland and sought to live and work in Scotland. Urban industries and expanding transport systems offered jobs in factories, and to build railways, canals, bridges and roads.

Areas in cities, such as Edinburgh's Cowgate and Canongate were called "Little Ireland". Many Irish Catholics settles in the east end of Glasgow and in communities across the west of Scotland in particular, to seek work in industries such as mining and textiles. These settlements led to increased competition for employment and housing and this led to antagonism and conflict between competing groups of workers over housing and jobs.

Discrimination in employment also fuelled tensions between the Catholic and Protestant communities in Scotland. Opportunities in employment were denied to people of both denominations on the grounds of their faith. Discriminatory recruitment practices were conducted unofficially and a name considered traditionally Protestant or Catholic, or whether a candidate attended a Catholic or non-Catholic school, was sufficient grounds for some businesses to reject applications for employment.

Sports clubs were founded as a focal point for these Catholic communities. For examples, Hibernian Football Club was founded in Edinburgh in 1875, and Glasgow Celtic Football Club was established in 1888. Later, in Dundee, Dundee Hibernian later became Dundee United. Football teams, whether they developed from a mainly Irish Catholic or Scottish Protestant community, played matches between one another for charities and to win competitions. Today, the increasing diversity and growing secularity of Scotland's population means that no football clubs are tied to any particular religion and supporters of all teams are typically from a range of racial, ethnic and religious backgrounds.

Sectarianism in Scotland today is perhaps most visible in relation to football. The historical links of some clubs and the traditional ethnic and religious make-up of their supporters have led to them being held as symbols of religious, cultural and political beliefs. An element of supporters following clubs such as Glasgow-based Rangers and Celtic and Edinburgh's Hibernian and Hearts use songs, chants and banners on match days to express abuse or support towards the Protestant or Catholic faiths. In a similar way, some fans also promote the activities of Northern Irish-based terrorist groups such as the IRA and UVF. At some matches this can generate an atmosphere of hatred, religious tension and intimidation which regularly leads to violence in communities across Scotland.

Sectarian language is commonly used in Scotland, with abusive terms such as "Hun" and "Orange bastard" being used against Protestants and others such as "Fenian" and "Tim" used to persecute Catholics. This reinforces religious and racial stereotypes as well as the divisions and conflict between the denominations.

In recent years, the challenge against sectarianism in Scotland has made significant progress. The problems associated with religious conflict are being examined and confronted across society by schools, community groups, academics, football clubs such as Celtic and Rangers, football governing bodies, national and local governments, churches, charities, museums, galleries and a growing number of individuals across the nation.