Witsum (Danish: Vitsum, North Frisian: Wiisem) is a municipality on the island of Föhr, in the district of Nordfriesland, in Schleswig-Holstein, Germany.

Many seabirds (migratory birds among them) use the stream Godel, the only "river" on Föhr, to hatch.

Witsum and the neighbouring village of Utersum were the only municipalities in the second zone of the Schleswig Plebiscites to vote for Denmark in 1920; yet because they were not directly situated at the border, the two of them remained with Germany.

With less than 70 inhabitants, Witsum has, according to article 54 of the Schleswig-Holstein Gemeindeordnung, a town meeting instead of a council.

The State Road that connects Wyk auf Föhr with Utersum runs through Witsum.