IP隧道是指一种可在两网络间用网际协议进行通信的信道。在该信道里，会先封装其他网络协议的数据包，之后再传输信息。

IP隧道经常用于连接两个不是用路由直接链接的IP网络，IP隧道会通过底层路由协议来架构中间传输网络。若IP隧道与两个或多个IPSec一起使用时，可以创建虚拟专用网（Virtual Private Network，VPN），让二个或多个被公开网络（如因特网）隔开的私有网络彼此访问，另一个主要应用也是目前常用的，让各IPv6网络隔着IPv4网络上通信。

在IP隧道中，每个IP包、来源/目的地址信息都被封装在一个数据包中，该数据包用于实际物理网络传递。

An IP tunnel is an Internet Protocol (IP) network communications channel between two networks. It is used to transport another network protocol by encapsulation of its packets.

IP tunnels are often used for connecting two disjoint IP networks that don't have a native routing path to each other, via an underlying routable protocol across an intermediate transport network. In conjunction with the IPsec protocol they may be used to create a virtual private network between two or more private networks across a public network such as the Internet. Another prominent use is to connect islands of IPv6 installations across the IPv4 Internet.