Ytterby (Swedish pronunciation: [ˈʏ̂tːɛrˌbyː]) is a village on the Swedish island of Resarö, in Vaxholm Municipality in the Stockholm archipelago. Today the residential area is dominated by suburban homes.
The name of the village translates to "outer village". Ytterby is most famous for being the single richest source of elemental discoveries in the world; the chemical elements yttrium (Y), terbium (Tb), erbium (Er), and ytterbium (Yb) are all named after Ytterby, and five more elements were also first discovered there.
Local roads connect Ytterby to county road 274 and hence the mainland. Except for the winter months, passenger ships of the Waxholmsbolaget call at a pier in Ytterby, providing a connection to Vaxholm town and Stockholm.