"Unreformed House of Commons" is a name given to the House of Commons of Great Britain before it was reformed by the Reform Act 1832, the Irish Reform Act 1832, and the Scottish Reform Act 1832.

The House of Commons of Great Britain was the lower house of the Parliament of Great Britain between 1707 and 1801. In 1707, as a result of the Acts of Union of that year, it replaced the House of Commons of England and the third estate of the Parliament of Scotland, as one of the most significant changes brought about by the Union of the kingdoms of England and Scotland into the Kingdom of Great Britain.