Microsoft Office Access, previously known as Microsoft Access, is a relational database management system from Microsoft that combines the relational Microsoft Jet Database Engine with a graphical user interface and software development tools. It is a member of the Microsoft Office suite of applications and is included in the Professional and higher versions for Windows and also sold separately. There is no version for MacOS or for Microsoft Office Mobile.

Access stores data in its own format based on the Access Jet Database Engine. It can also import or link directly to data stored in other Access databases, Excel, SharePoint lists, text, XML, Outlook, HTML, dBase, Paradox, Lotus 1-2-3, or any ODBC-compliant data container including Microsoft SQL Server, Oracle, MySQL and PostgreSQL. Software developers and data architects can use it to develop application software and non-programmer "power users" can use it to build simple applications. It supports some object-oriented techniques but falls short of being a fully object-oriented development tool.[
Access version 1.0 was released in November 1992, quickly followed in May 1993 by an Access 1.1 release to improve compatibility with other Microsoft products and include the Access Basic programming language.

Microsoft specified the minimum hardware requirements for Access v2.0: Microsoft Windows v3.0 with 4 MB of RAM required, 6 MB RAM recommended; 8 MB of available hard disk space required, 14 MB hard disk space recommended. The product was shipped on seven 1.44 MB diskettes. The manual shows a 1993 copyright date.

Originally, the software worked well with relatively small databases but testing showed some circumstances caused data corruption. For example, file sizes over 10 MB were problematic (note that most hard disks were smaller than 500 MB at the time this was in wide use), and the Getting Started manual warns about a number of circumstances where obsolete device drivers or incorrect configurations can cause data loss. With the phasing out of Windows 95, 98 and ME, improved network reliability, and Microsoft having released 8 service packs for the Jet Database Engine, the reliability of Access databases has been vastly improved in both size and number of users.

With Office 95, Microsoft Access 95 became part of the Microsoft Office Professional Suite joining Microsoft Excel, Word, and PowerPoint and transitioning from Access Basic to Visual Basic for Applications (VBA). Since then, there have been releases of Microsoft Access with each release of Office. This includes Access 97 (version 8.0), Access 2000 (version 9.0), Access 2002 (version 10.0), Access 2003 (version 11.0), and Access 2007 (version 12.0).

The native Access database format (the Jet MDB Database) has also evolved over the years. Formats include Access 1.0, 1.1, 2.0, 95, 97, 2000, and 2002-2007. The most significant transition was from the Access 97 to the Access 2000 format which was not backward compatible, and Access 2000 required the new format. Since Access 2000, all newer versions of Access support the Access 2000 format. New features were added to the Access 2002 format which can be used by Access 2002, 2003, and 2007.