Lyttelton Line is a name sometimes used to refer to the section of the Main South Line in New Zealand's South Island between Lyttelton and Christchurch, and can also be used to refer to the operations on this section. As it has always been part of the Main South Line, this name has never been officially used to refer to the track itself.

Lyttelton is a port town on the north shore of Lyttelton Harbour / Whakaraupō, at the northwestern end of Banks Peninsula and close to Christchurch, on the eastern coast of the South Island of New Zealand.