The Sixth Periodic Review of Westminster constituencies, also known as the 2013 Review, 2018 Review, or just boundary changes, was an ultimately unfruitful cycle of the process by which constituencies of the House of Commons of the United Kingdom are reviewed and redistributed. The four UK boundary commissions carried out their reviews between 2011 and 2018, but their recommendations were not taken up by the government and were formally laid aside in 2020.