Marguerite Viby (25 June 1909 – 8 April 2001) was a Danish actress of stage, film and television.

Considered one of the great comedy actresses of Danish cinema, Viby received honorary Bodil and Robert Awards in 2000 for lifetime achievement.

According to Danish film historian Morten Piil, it was Viby's next role which established her most noted persona—the energetic, witty woman who acts as she necessary to maneuver in a man's world.

In the 1932 George Schnéevoigt film Tretten År (13 Years), Viby was an office girl who plays a thirteen-year-old Lolita to avoid men's advances.

The style of direction—quick light-hearted banter similar to American screw-ball comedies—was better suited to Viby than the heavier exposition of Gregers direction.

She quickly became one of the most popular actresses and performed in a string of romantic comedies including Som du vil ha' mig-!

Her first marriage was to actor and dancer Poul Christian Guldager (1926–1931), then to Danish film director Emanuel Gregers (1932–1938).