Files with the .MPP extension contain MS Project data such as time lines, task lists, and other project information. The data is used for scheduling, burden control, finance, and other aspects of the project.

The Microsoft Project software is designed for organizing, maintaining and tracking progress in projects and saves its projects in the MPP format by default. The files can, however, also be opened using numerous browsers that support this format. Not every version of Microsoft Project software will support every type of MPP file.