This volume constitutes the refereed proceedings of the 26th International Symposium on String Processing and Information Retrieval, SPIRE 2019, held in Segovia, Spain, in October 2019.The 28 full papers and 8 short papers presented in this volume were carefully reviewed and selected from 59 submissions. They cover topics such as: data compression; information retrieval; string algorithms; algorithms; computational biology; indexing and compression; and compressed data structures.
