Embodiments may include a system configured to receive search session data that indicates, for each of multiple search sessions performed by a respective user, multiple search queries submitted by that user during the search session. The system may also receive search selection data that indicates, for each of multiple search queries resulting in a set of search results, a particular item selected from that set of search results by a respective user. The system may be configured to perform a co-occurrence analysis on the search data in order to generate one or more search indices that specify, for a given search query, one or more search queries determined to be related to the given search query according to the co-occurrence analysis. The system may be configured to process a client request for related queries that are related to a query of interest submitted by the user within that request.