Otto Monsen (August 19, 1887 – December 14, 1979) was a Norwegian track and field athlete who competed in the 1908 Summer Olympics and in the 1912 Summer Olympics.^[1]

In 1908 he participated in the high jump competition but failed to clear a height. Four years later he participated in the high jump competition again. He cleared 1.75 metre but did not qualify for the final. He finished tied for 13th.^[2]