Brainwashing (also known as mind control, menticide, coercive persuasion, thought control, thought reform, and forced re-education) is the concept that the human mind can be altered or controlled by certain psychological techniques. Brainwashing is said to reduce its subject's ability to think critically or independently, to allow the introduction of new, unwanted thoughts and ideas into their minds, as well as to change their attitudes, values, and beliefs.

The term "brainwashing" was first used in English by Edward Hunter in 1950 to describe how the Chinese government appeared to make people cooperate with them during the Korean War. Research into the concept also looked at Nazi Germany, at some criminal cases in the United States, and at the actions of human traffickers. In the late 1960s and 1970s, the CIA's MKUltra experiments failed with no operational use of the subjects. Scientific and legal debate followed, as well as media attention, about the possibility of brainwashing being a factor when Lysergic acid diethylamide (LSD) was used, or in the conversion of people to groups which are considered to be cults. The concept of brainwashing is sometimes involved in lawsuits, especially regarding child custody. Courts worldwide used to reject expert witnesses who claimed there was a "brainwashing". It can also be a theme in science fiction and in political and corporate culture. In casual speech, "brainwashing" and its verb form, "brainwash", are used figuratively to describe the use of propaganda to persuade or sway public opinion. The concept of brainwashing is not generally accepted as a scientific term.