MySQL（官方发音为英语发音：/maɪˌɛskjuːˈɛl/“My S-Q-L”，但也经常读作英语发音：/maɪˈsiːkwəl/“My Sequel”）原本是一个开放源码的关系数据库管理系统，原开发者为瑞典的MySQL AB公司，该公司于2008年被升阳微系统（Sun Microsystems）收购。2009年，甲骨文公司（Oracle）收购升阳微系统公司，MySQL成为Oracle旗下产品。

MySQL在过去由于性能高、成本低、可靠性好，已经成为最流行的开源数据库，因此被广泛地应用在Internet上的中小型网站中。随着MySQL的不断成熟，它也逐渐用于更多大规模网站和应用，比如维基百科、Google和Facebook等网站。非常流行的开源软件组合LAMP中的“M”指的就是MySQL。

MySQL (officially pronounced as /maɪ ˌɛskjuːˈɛl/ "My S-Q-L",) is an open-source relational database management system (RDBMS). In July 2013, it was the world's second most widely used RDBMS, and the most widely used open-source client–server model RDBMS. It is named after Michael Widenius' (who is a co-founder of MySQL) daughter, My, while "SQL" stands as the abbreviation for Structured Query Language. The MySQL development project has made its source code available under the terms of the GNU General Public License, as well as under a variety of proprietary agreements. MySQL was owned and sponsored by a single for-profit firm, the Swedish company MySQL AB, now owned by Oracle Corporation. For proprietary use, several paid editions are available, and offer additional functionality.