Vallensbæk is a seaside western suburb located in Denmark as part of the Greater Copenhagen Area. It serves as its own administrative district, known as Vallensbæk Municipality, which is recognized as one of the smallest municipalities in the country.
The town borders Køge Bay and includes the Køge Bay Beach Park along its coastline. Geographically, the suburb is divided into two distinct sections that are not directly connected to each other: Vallensbæk Nordmark in the north and Vallensbæk Strand in the south. Although separated, these two areas are commonly referred to together as Vallensbæk.