Microsoft Exchange Server是微软公司的一套电子邮件服务组件。除传统的电子邮件的访问、储存、转发作用外，在新版本的产品中亦加入了一系列辅助功能，如语音邮件、邮件过滤筛选、OWA（基于Web的电子邮件访问）。Exchange Server支持多种电子邮件网络协议，如SMTP、NNTP、POP3、IMAP4。Exchange Server能够与微软公司的活动目录完美结合。

Exchange Server是个消息与协作系统，Exchange server可以被用来构架应用于企业、学校的邮件系统甚至于免费邮件系统。也可以用于开发工作流，知识管理系统，Web系统或者是其他消息系统。

Microsoft Exchange Server is a calendaring and mail server developed by Microsoft that runs exclusively on the Microsoft Windows Server product line.

Exchange Server was initially Microsoft's internal mail server. The first version of Exchange Server to be published outside Microsoft was Exchange Server 4.0. Exchange initially used the X.400 directory service but switched to Active Directory later. Versions 4.0 and 5.0 came bundled with an email client called Microsoft Exchange Client. It was discontinued in favor of Microsoft Outlook.