ASP stands for Active Server Pages and is a Microsoft web application framework used to build dynamic websites. ASP files contain HTML, text, and script tags where scripts are executed on the server. ASP runs on IIS web server which is included with Windows. ASP.NET was released in 2002 as the successor to ASP and is built on the .NET framework, allowing programmers to write code in any .NET language. ASP.NET supports web forms, MVC, and web pages development models.