Rømø (German: Röm, Frisian: Romeach) is a Danish island in the Wadden Sea. Rømø is part of Tønder municipality. The island has 650 inhabitants as of 1 January 2011 and covers an area of 129 km². Rømø is a popular tourist spot each year, attracted by the clothing optional beaches which can be driven on with motor vehicles legally.
Rømø is now the southernmost of Denmark's Wadden Sea Islands (the previous being the small uninhabited island of Jordsand which sank in 1999). It is linked to the Danish mainland by a road running across a causeway, and the island also lies only about 3 km from the neighbouring German island Sylt, to which it is connected by ferry. It is home to a number of small communities such as Kongsmark, Østerby, Lakolk, and Sønderstrand.