Franz August Otto Pieper (June 27, 1852 – June 3, 1931) was a Confessional Lutheran theologian who also served as the fourth president of what was known at that time as the German Evangelical Lutheran Synod of Missouri, Ohio, and Other States (Missouri Synod).

Pieper was born at Karwitz, Pomerania, (85 miles (137 km) west of Danzig) and died in St. Louis, Missouri. After studying at the gymnasium of Kolberg, Pomerania, he emigrated to the United States in 1870. He graduated from Northwestern College in Watertown, Wisconsin, in 1872 and from Concordia Seminary in St. Louis in 1875. He was a Lutheran pastor from 1875 to 1878, serving first at Centerville, Wisconsin, and then at Manitowoc, Wisconsin. He became a professor of theology at Concordia Seminary in 1878, and in 1887 he became president of the same institution. He also served as editor of Lehre und Wehre, the faculty journal of Concordia Seminary.

From 1882 to 1899, Pieper served on the Board of Colored Missions for the Evangelical Lutheran Synodical Conference of North America. He then served as the fourth president of the Missouri Synod from 1899 to 1911.

As a systematic theologian, Franz Pieper's magnum opus, Christliche Dogmatik (1917–1924), provided the modern world with a learned and extensive presentation of orthodox Lutheran theology. Translated into English as Christian Dogmatics (1950–1953), it continues to be the basic textbook of doctrinal theology in the Missouri Synod. He was also the main author of A Brief Statement of 1932, an authoritative presentation of the synod's doctrinal stance.