Nikolaus Gjelsvik (11 April 1866 –14 November 1938) was a Norwegian jurist and law professor.

Among his works are the books Innleiding i rettsstudiet from 1912, Lærebok i folkerett from 1915, and Lærebok i millomfolkeleg privatrett from 1918.

He was a proponent for the Nynorsk language, took part in organisational work, and had leading positions in the publishing house Det Norske Samlaget and in the societies Noregs Ungdomslag and Noregs Mållag.

[1][2][3] Marshals at his funeral were Nicolai Rygg and Ferdinand Schjelderup.

This biographical article about a Norwegian academic is a stub.