Milla Grosberghaugen Andreassen (born 4 August 2005) is a Norwegian cross-country skier. She is a six-time Junior World Champion.
Andreassen competed at the 2025 Nordic Junior World Ski Championships and won gold medals in the 10 kilometre freestyle, 20 kilometre mass start, and 4 x 5 kilometre relay. She also won a bronze medal in the sprint classical.
In January 2026, she was selected to represent Norway at the 2026 Winter Olympics.