A technique is provided for prefetching data items. An apparatus has a storage structure with a plurality of entries to store data items. The storage structure is responsive to access requests from processing circuitry to provide access to the data items. The apparatus has prefetch circuitry to prefetch data and correlation information storage to store correlation information for a plurality of data items. The correlation information identifies, for each of the plurality of data items, one or more correlated data items. The prefetch circuitry is configured to monitor the access requests from the processing circuitry. In response to detecting a hit in the correlation information storage for a particular access request that identifies a requested data item for which the correlation information storage stores correlation information, the prefetch circuitry is configured to prefetch the one or more correlated data items identified by the correlation information for the requested data item.