多用途互联网邮件扩展（MIME，Multipurpose Internet Mail Extensions）是一个互联网标准，它扩展了电子邮件标准，使其能够支持：

MIME改善了由RFC 822转变而来的RFC 2822，这些旧标准规定电子邮件标准并不允许在邮件消息中使用7位ASCII字符集以外的字符。正因如此，一些非英语字符消息和二进制文档，图像，声音等非文本消息原本都不能在电子邮件中传输（MIME可以）。MIME规定了用于表示各种各样的数据类型的符号化方法。此外，在万维网中使用的HTTP协议中也使用了MIME的框架，标准被扩展为互联网媒体类型。

A media type (also MIME type and content type) is a two-part identifier for file formats and format contents transmitted on the Internet. The Internet Assigned Numbers Authority (IANA) is the official authority for the standardization and publication of these classifications. Media types were first defined in Request for Comments 2045 in November 1996, at which point they were named MIME (Multipurpose Internet Mail Extensions) types.