通用中间语言（Common Intermediate Language，简称CIL，发音为"sill"或"kill"）是一种属于通用语言架构和.NET框架的低级（lowest-level）的人类可读的编程语言。目标为.NET框架的语言被编译成CIL，然后汇编成字节码。CIL类似一个面向对象的汇编语言，并且它是完全基于堆栈的。它运行在虚拟机上，其主要的语言有C♯、Visual Basic .NET、C++/CLI以及J♯。

在.NET语言的测试版中，CIL原本叫做微软中间语言，即Microsoft Intermediate Language，简称MSIL。由于C#和通用语言架构的标准化，在.Net开发平台下，所有语言（C♯、VB.NET、J♯、Managed C++）都会被编译为MSIL，再由CLR负责运行，字节码现在已经官方地成为了CIL。因此MSIL有时仍会与CIL混用，特别是那些.NET语言的老用户。更详细的信息可以参看微软的说明。

Common Intermediate Language (CIL, pronounced either "sil" or "kil"), formerly called Microsoft Intermediate Language or MSIL, is the lowest-level human-readable programming language defined by the Common Language Infrastructure (CLI) specification and is used by the .NET Framework and Mono. Languages which target a CLI-compatible runtime environment compile to CIL, which is assembled into an object code that has a bytecode-style format. CIL is an object-oriented assembly language, and is entirely stack-based. Its bytecode is translated into native code or — most commonly — executed by a virtual machine.