IBD is a MySQL database tablespace file. IBD extension is associated with InnoDB database storage engine, available under GNU open-source license and used by default by MySQL version 5.5 and later.

IDB files stores tables that constitute a database. IDB cannot be moved or copied manually – a proper backup copy must be created with "mysqlbackup" command in order to use the file with other database. IDB format was developed by Finnish company Innobase Oy, and in 2006 was acquired by Oracle Corporation, which currently maintains it.