MySQL AB (founded 1995) is a subsidiary of Sun Microsystems, dual headquartered in Uppsala, Sweden and Cupertino, California, USA with offices in other countries (Paris, France; Munich, Germany; Dublin, Ireland; Milan, Italy; and Tokyo, Japan). The company is the creator and owner of MySQL, a relational database management system as well as related products such as MySQL Cluster.

With around 400 employees in 25 countries, MySQL AB is one of the largest open source companies worldwide. Around 70% of the employees work for MySQL from their home offices.

On 16 January 2008, MySQL AB announced that it had agreed to be acquired by Sun Microsystems for approximately US$1 billion. The acquisition completed on 26 February 2008.

Together with Linux, Apache, and PHP, the MySQL Server forms one of the building blocks of the LAMP technology stack. The company claims a user base of over 5 million MySQL installations worldwide and over 10 million product downloads in 2004.