Utersum (Fering North Frisian: Ödersem, Danish: Yttersum) is a municipality on the island of Föhr, in the district of Nordfriesland, in Schleswig-Holstein, Germany.

The village is located between pine woods and dunes in the utmost southwest of Föhr, within the sight of the neighbouring islands of Amrum and Sylt.

A bus service links the place to the other villages on Föhr and to the town of Wyk.

[5] Utersum, Hedehusum and the adjacent municipality of Witsum were the only ones in Zone II of the Schleswig Plebiscites in 1920 to vote for Denmark; as they were not directly situated at the border though, they remained with Germany.

Utersum was the hometown of Volkert & Boz Lorenzen and Arian Martens all able seaman lost at sea on the brig Mary Celeste in 1872.