An extension of the ISO 9660:1988 ISO standard file system for CD-ROMs that allows Unicode characters in file names and other enhancements. Version 1 of Joliet was released on 1995-05-22.

Joiliet supports file and directory names up to 128 bytes (64 unicode characters) long, directory names with file name extensions, a directory hierarchy deeper than 8 levels and the volume recognition sequence supports multisession.

Joliet uses ISO 9660's "supplementary volume descriptor" (SVD) to specify Unicode files. Use of the previously unused escape sequence ISO 2022 means that Joliet is backward compatible with ISO 9660..