Gas transmission system is a gas pipeline system and associated facilities designed for gas supply to consumers. A gas transmission system is a link between gas fields and gas consumers. A gas transmission system is the basis of the Unified Gas Supply System (UGSS) of Russia.

A gas transmission system includes: gas trunklines, distribution pipelines, pipeline bridges, branches and infeed gas pipelines. Considerable remoteness of gas fields from consumption areas causes necessity for construction of huge gas transmission systems.