The London Encyclopaedia, first published in 1983, is a 1,100-page historical reference work on London, the capital city of the United Kingdom, covering the whole of the Greater London area.

The first edition of the encyclopaedia was compiled over a number of years by the antiquarian bookseller Ben Weinreb and the historian Christopher Hibbert. Revised editions were published in 1993, 1995 and 2008. It has around 5,000 articles, supported by two indices, one general and one listing people, each with about 10,000 entries, and is published by Macmillan.

In 2012, an app was developed by Heuristic-Media and released as London—A City Through Time. Toby Evetts and Simon Reeves, partners in Heuristic-Media, discussed the development of the app with The Guardian in 2013, describing how 4,500 entries had to be plotted onto a guide map by hand.

The encyclopaedia builds on a number of earlier publications, including:

Media related to The London Encyclopaedia at Wikimedia Commons