Linn Catharina Cavallius Githmark[1] (born 26 September 1982) is a Norwegian curler who has skipped her country to a world junior title, and also played on the Norwegian team that won a silver medal at the world championships.

Githmark played on the teams representing Norway in world junior championships from 1997 to 2004, and was skip on all but two occasions.

Githmark made her world championship debut in 2004, taking Hanne Woods' place as third on the team skipped by former world champion Dordi Nordby.

Githmark posed for Ana Arce's "Fire on Ice" 2007 Team Sponsorship Calendar to promote women's curling.

Githmark represented Norway at the inaugural 2008 World Mixed Doubles Curling Championship, partnered with her father Tormod Andreassen.