A cross-platform is a programming language, software application or hardware device that works on more than one system platform (e.g. Unix, Windows, Macintosh). Examples of cross-platform languages are Java, JavaScript, HTML, Perl, Python, REALbasic_programming_language, and the Revolution_programming_language.

There are also cross-platform extensions for many programming languages that enable programmers to compile/run the same source code with minimal fixes on different platforms. An example is wxWindows.