Methods, systems, and apparatus, including computer programs encoded on computer storage media, for revising search queries. One of the methods includes receiving an original search query submitted by a user of a user device; determining that the original search query is similar to a first search query of a plurality of search queries previously submitted by the user; selecting a first term that appears in the first search query and not in the original search query, wherein selecting the first term comprises determining that the first term appears in at least a threshold number of other distinct search queries of the plurality of search queries previously submitted by the user; generating a revised search query by adding the first term that appears in the first search query to the original search query; and obtaining search results for the revised search query from a search engine.