A launch service provider (LSP) is a type of company which specialises in launching spacecraft. It is responsible for the ordering, conversion or construction of the carrier rocket, assembly and stacking, payload integration, and ultimately conducting the launch itself. Some of these tasks may be delegated or sub-contracted to other companies. For example, United Launch Alliance has formally subcontracted the production of GEM solid rocket motors for their Delta II and Delta IV (Medium version) rockets to Alliant Techsystems, both vehicles are now retired. An LSP does not necessarily build all the rockets it launches.
In some cases, an LSP is not required to launch a rocket. Government organizations such as the military and defense forces may conduct the launch themselves.