Lèse Majesté is an authoritarian and repressive law that is headed by Section 112 of the Thai Penal Code. It is illegal to defame, insult or threaten the king, queen, heir or regents. The law of lesa majesty has been in force since 1908. The punishment is three to fifteen years in prison on charge and has been described as the "toughest law of the majesty of the world" and "possibly the strictest criminal defamation law in anywhere". Disregarding the call of the late King Bumibhol Adulyadej that he insisted that he should be criticized if something does wrong, otherwise they would not be treating him like a human being.

Complaints by Lèse-majesté can be filed by any person against another person, and must always be formally investigated. The details of the charges are rarely made public. A defendant in section 112 always encounters obstructions from the beginning to the end of a case, especially when requesting a provisional release. There are months-long preventive detentions, and defendants are denied bail. The United Nations Working Group on Arbitrary Detention determined in August 2012 that the preventive detention of a suspected criminal of the majesty violated international human rights law. The courts do not seem to recognize the principle of granting the benefit of the doubt to the accused. The judges have said that the accusers did not have to prove the veracity of the alleged lèse-majesté material, but only to affirm that it defames in some way. To plead guilty is seen as a movement to seek real forgiveness.

The coup leaders, since the coup d'etat in 1976, have regularly cited an increase in alleged Lèse-Majesté as a prerequisite to overthrow an elected government. The coup d'etat of 2006, when lèse-majesté was cited as one of the main reasons, marked an increase in the cases of lèse-majesté. After the 2014 Thai coup d'etat, Thailand had the highest number of prisoners of Les Majesty in the history of the nation. The board granted authority to the military courts to prosecute lèse-majesté. In most cases, convictions result in severe penalties. The longest sentence recorded was 60 years in prison (halved because the defendant pleaded guilty). Secret trials and severe punishments have also been used.