The coat of arms of Hoorn is a coat of arms that has been in uses since the middle ages. Over time it underwent some changes, the coat of arms hasn't been changed since it was acknowlaged in use by the High Council of Nobility 1816. At present day it is, in unchanged form, the coat of arms of the municipality of Hoorn. The current municipality was formed in 1979 by merging the city of Hoorn with the villages Zwaag and Westerblokker, it was decided to use the old coat of arms as coat of arms of the new municipality.