Microsoft Java虚拟机（Microsoft Java Virtual Machine，缩写：MSJVM）是微软所推出的Java虚拟机。为了支持颇受欢迎的Java applet，于是微软免费推出此项程序，使得其自家的浏览器－Internet Explorer 3也可以在网页中运行Applet。不过微软的此项举动于1997年10月遭到Java的开发商、同时也是其竞争对手的升阳微系统（Sun Microsystems）指控侵权，最后双方和解，微软也终止了对Microsoft Java虚拟机的开发及支持，但现今仍偶尔可见Microsoft Java虚拟机继续被用户使用的情况。

The Microsoft Java Virtual Machine (MSJVM) is a discontinued proprietary Java virtual machine from Microsoft. It was first made available for Internet Explorer 3 so that users could run Java applets when browsing on the World Wide Web. It was the fastest Windows-based implementation of a Java virtual machine for the first two years after its release. Sun Microsystems, the creator of Java, sued Microsoft in October 1997 for incompletely implementing the Java 1.1 standard. It was also named in the United States v. Microsoft antitrust civil actions, as an implementation of Microsoft's Embrace, extend and extinguish strategy. In 2001, Microsoft settled the lawsuit with Sun and discontinued its Java implementation.