Christian Lous Lange (17 September 1869 – 11 December 1938) was a Norwegian historian, teacher, and political scientist.

He graduated from secondary school in 1887 and proceeded to travel and study history, English, and French at the University of Oslo, from which he received the cand.

Lange rejoined the Inter-Parliamentary Union in 1909 when he was appointed secretary general of the organization, a position he would retain until 1933.

He remained active in numerous other organizations as well, acting as Norway's delegate or alternate delegate to the League of Nations from its founding until 1938, writing reports and acting as a correspondent for the Carnegie Endowment for International Peace, and participating in the Dutch sponsored Central Organisation for Durable Peace, among other activities.

She was imprisoned at Grini concentration camp in September 1943, but fell ill and died at Ullevål Hospital in December.