The Silver Jubilee of Elizabeth II marked the 25th anniversary of the accession of Queen Elizabeth II on 6 February 1952. It was celebrated with large-scale parties and parades throughout the United Kingdom and the Commonwealth throughout 1977, culminating in June with the official "Jubilee Days", held to coincide with the Queen's Official Birthday. The anniversary date itself was commemorated in church services across the land on 6 February 1977, and continued to be for the rest of that month. In March, preparations started for large parties in every major city of the United Kingdom, as well as for smaller ones for countless individual streets throughout the country.

Elizabeth II was Queen of the United Kingdom and other Commonwealth realms from 6 February 1952 until her death in 2022. She was queen regnant of 32 sovereign states over the course of her lifetime and remained the monarch of 15 realms by the time of her death. Her reign of 70 years and 214 days is the longest of any British monarch or female monarch, and the second longest verified reign of any monarch of a sovereign state in history.