Disinformation is false or inaccurate information that is spread deliberately. It is synonymous with and sometimes called Black propaganda. It may include the distribution of forged documents, manuscripts, and photographs, or propagation of malicious rumors and fabricated intelligence. Disinformation should not be confused with misinformation, information that is unintentionally false.

In espionage or military intelligence, disinformation is the deliberate spreading of false information to mislead an enemy as to one's position or course of action. In politics, disinformation is the deliberate attempt to deflect voter support of an opponent, disseminating false statements of innuendo based on the candidates vulnerabilities as revealed by opposition research. In both cases, it also includes the distortion of true information in such a way as to render it useless.

Disinformation techniques may also be found in commerce and government, used to try to undermine the position of a competitor. It is an act of deception and blatant false statements to convince someone of an untruth. Cooking-the-books might be considered a disinformation strategy that led to the Sarbanes-Oxley Act.

Unlike traditional propaganda and Big Lie techniques designed to engage emotional support, disinformation is designed to manipulate the audience at the rational level by either discrediting conflicting information or supporting false conclusions.

Another technique of concealing facts, or censorship, is also used if the group can effect such control. When channels of information cannot be completely closed, they can be rendered useless by filling them with disinformation, effectively lowering their signal-to-noise ratio and discrediting the opposition by association with a lot of easily-disproved false claims.

A common disinformation tactic is to mix some truth and observation with false conclusions and lies, or to reveal part of the truth while presenting it as the whole (a limited hangout).

The Cold War made disinformation a recognized military and political tactic. Military disinformation techniques were described by Vladimir Volkoff.