Lake Marian is a lake in the Darran Mountains in the Fiordland National Park in the South Island of New Zealand.
It is fed and drained by Marian Creek which in turn feeds into the Hollyford River. A tramping track leads to the lake from the Hollyford River valley road. The lake was named by surveyor E.H Wilmot after his cousin Marian Little. The Marian Valley is a perfect example of a hanging valley, the remaining legacy of a tributary glacier that met the main Hollyford Glacier.