Pinnau is an Amt ("collective municipality") in the district of Pinneberg, in Schleswig-Holstein, Germany. The Amt Pinnau was formed in January 2007 by the merger of the Ämter Bönningstedt and Pinneberg-Land. The seat of the Amt is in Rellingen, itself not part of the Amt.

The Amt Pinnau consists of the following municipalities:

1. Borstel-Hohenraden
2. Ellerbek
3. Kummerfeld
4. Prisdorf
5. Tangstedt

53°41′N 9°50′E / 53.683°N 9.833°E / 53.683; 9.833