Otto III (died September 28, 1057), called the White and known as Otto of Schweinfurt, wais the margrave of the Nordgau (1024–1031) and duke of Swabia (1048–1057).

He is the son of Henry of Schweinfurt, margrave of the Nordgau, and Gerberga of Henneberg.

He is one of the most powerful East Franconian princes by inheritance: having extensive land in the Radenzgau and Schweinfurt.

In 1014, he first appears as count of Lower Altmühl (or Kelsgau) and, in 1024, he inherits his father's march.

In 1034, he becomes count of the Lower Naab.

From then on to his appointment to Swabia, he takes part in many imperial expeditions into Bohemia, Hungary, and Poland.