Pinneberg is a Kreis (district) in the southwestern part of Schleswig-Holstein, Germany. It is situated at the northern bank of the Elbe river. Area 664 kmē, population 291,700 (2002). The district's capital is the city of Pinneberg.

While Pinneberg is the smallest district within Schleswig-Holstein, it has the most inhabitants. Due to the growing Hamburg metropolitan area the population is still increasing. The district consists of the northwestern suburbs of Hamburg, e.g. Pinneberg, Elmshorn, Quickborn and Wedel.

Although the district of Pinneberg has no access to the sea, the islet of Helgoland is a part of this district.