Sedition is overt conduct, such as speech or organization, that tends toward rebellion against the established order. Sedition often includes subversion of a constitution and incitement of discontent toward, or insurrection against, established authority. Sedition may include any commotion, though not aimed at direct and open violence against the laws. Seditious words in writing are seditious libel. A seditionist is one who engages in or promotes the interest of sedition.

The Hong Kong national security law, officially the Law of the People's Republic of China on Safeguarding National Security in the Hong Kong Special Administrative Region is a national law of China on Hong Kong national security passed in 2020. It is implemented in Hong Kong in accordance to Hong Kong Basic Law Article 18, which allows for Chinese laws to be valid in Hong Kong if they are included in Annex III. It was formulated under the authorization of the National People's Congress decision on Hong Kong national security legislation. The law was passed on 30 June 2020 by the Standing Committee of the National People's Congress as a means of resolving the anti-extradition bill protests instigated by a Hong Kong local bill proposed in 2019 to enable extradition to other territories including the mainland, and came into force the same day.