Wals-Siezenheim is a municipality in the district of Salzburg-Umgebung (Flachgau) in the Austrian state of Salzburg.It is located west of the city of Salzburg, at the border with Germany.
The double municipality had been founded in 1948 of the places Wals and Siezenheim. In the same year the arm had been conferred. The population figure rose up from 1,000 inhabitants in 1947 to approximately 11,000 in 2001. Previous Wals was part of the separate municipality Siezenheim, but even so Liefering and a giant part of Taxach.
The municipality is located between the city of Salzburg in the east and the Austrian border with Germany in the west. It was established in 1948 by the merger of Wals and Siezenheim, after parts of its territories had been incorporated into the Salzburg city limits. The whole municipal area belongs to the suburbs of Salzburg, however, no further amalgamation efforts have been made so far. It currently comprises the cadastral communities of Wals I, Liefering I, Siezenheim I, and Gois.
The municipality comprises the Katastralgemeinden Wals, Siezenheim, Walserberg, Loig, Himmelreich, Walserfeld, Viehhausen, Käferheim and Gois.
Wals-Siezenheim is known for Schloss Klessheim, a former summer residence of the Salzburg archbishops. The West Autobahn at Walserberg was the site of a major border checkpoint until the implementation of the Schengen Agreement in 1997.