The Constitution Protection Office^[1] (Hungarian: Alkotmányvédelmi Hivatal, "AH") is a Hungarian internal security intelligence agency, formerly known as Nemzetbiztonsági Hivatal (En. Office of National Security). Its primary responsibilities are: counterintelligence, anticorruption, economic security and related proactive measures. The AH also leads investigations against organized crime and deals with (mainly internal) threats against society (such as subversion).

AH is active since 2010.