„Party per fess wavy shield azure and Argent, above a bobbin Argent and beneath two crossed swords gules.“ 
The arms were granted on January 3, 1939. The upper part of the arms shows a bobbin, as at the time the textile industry was of great importance to the area. The base shows two crosswed swords, symbolising the medieval court (Freistuhl) in the municipality. The wavy division line symbolises the Ems river.
This image is taken from www.ngw.nl – Heraldry of the World –  an international civic heraldry site by Ralf Hartemink. http://www.ngw.nl/int/dld/g/greven.htm

Grevener Wappenkunde
unknown - constructed and added by Jürgen Krause