A national service of thanksgiving in the United Kingdom is an act of Christian worship, generally attended by the British monarch, Great Officers of State and Ministers of the Crown, which celebrates an event of national importance. Originally it started with the intention to give thanks for victory in battle. However it evolved to celebrate occasions such as a royal jubilee, a royal wedding anniversary, or the end of a conflict. These services are usually held at St Paul's Cathedral in the City of London.

St Paul's Cathedral is an Anglican cathedral in London, England, the seat of the Bishop of London. The cathedral serves as the mother church of the Diocese of London. It is on Ludgate Hill at the highest point of the City of London. Its dedication in honour of Paul the Apostle dates back to the original church on this site, founded in AD 604. The present structure, which was completed in 1710, is a Grade I listed building that was designed in the English Baroque style by Sir Christopher Wren. The cathedral's reconstruction was part of a major rebuilding programme initiated in the aftermath of the Great Fire of London. The earlier Gothic cathedral, largely destroyed in the Great Fire, was a central focus for medieval and early modern London, including Paul's walk and St Paul's Churchyard, being the site of St Paul's Cross.