The Chaos Computer Club says its members voted overwhelmingly in favour of the move late yesterday.
Spokeswoman Constanze Kurz said today that members of the group, which describes itself as "Europe's largest association of hackers," also pledged to financially support Snowden's efforts to avoid extradition to the US.
Snowden, who is currently in Russia, has been charged with espionage and other offenses in the US and could get 30 years in prison if convicted.