Disinformation refers to various propaganda techniques primarily associated with intelligence agencies’ manipulative activities directed at foreign countries and with military tactics directed at the enemy during wartime (where they form part of psychological warfare). Leaving aside military activities, this entry discusses disinformation associated with intelligence agencies. Locating these techniques within intelligence agencies’ three primary agenda-building strategies of secrecy, censorship, and propaganda helps highlight how comparatively little is known about disinformation. Recent leaks by national security whistle-blowers have significantly expanded our knowledge of contemporary disinformation techniques but raise ethical dilemmas for researchers.