Abstentionism is standing for election to a deliberative assembly while refusing to take up any seats won or otherwise participate in the assembly's business. Abstentionism differs from an election boycott in that abstentionists participate in the election itself. Abstentionism has been used by Irish republican political movements in the United Kingdom and Ireland since the early 19th century.

After the Act of Union 1800, Ireland was represented at Westminster in the House of Commons of the United Kingdom of Great Britain and Ireland. Repeal of the Act of Union was a goal of many Irish republicans.

In 1845, a motion was carried at the Repeal Association's committee for all Irish MPs to withdraw from Westminster. It was proposed by Thomas Osborne Davis of the Young Ireland movement. However, the committee felt that MPs already sitting could not withdraw without breaking the oath of office they had taken upon election. The Irish Confederation, which withdrew from the Repeal Association in 1847, resolved in favour of immediate abstention. However, William Smith O'Brien, its founder, continued to speak at Westminster. In 1848 Charles Gavan Duffy proposed that Irish MPs expelled from Westminster should sit in a separate Irish parliament.