XSP is a simple, standalone web server written in C# that hosts ASP.NET's System for Linux and other Unix operating systems. It runs on the mono runtime for Linux and the .NET Framework runtime, making it usable as a lightweight web server on any platform supporting .NET.
XSP was the original name of the internal project at Microsoft that became ASP.NET. The name pays homage to the original name of what became ASP.NET.
XSP may refer to:
- XSP (software), an ASP.NET server
- eXtensible Server Pages, a language in Apache Cocoon
- The IATA airport code of Seletar Airport, Singapore