The Hong Kong National Security Law is a piece of national security legislation passed on 30 June 2020 which was a major factor, besides the COVID-19 pandemic and its accompanying gathering regulations, in essentially ending the anti-extradition bill protests. The law established the crimes of secession, subversion, terrorism, and collusion with foreign organisations. Implementation of the law entitles authorities to surveil, detain, search and extradite persons suspected under its provisions to Mainland China.

A few local protests took place in November 2020 but there were no large-scale demonstrations in threat of the national security law. The detention of Joshua Wong, Agnes Chow and Ivan Lam on 23 November aroused international attention.

The national security law was also a factor in the dismantling of pro-democratic opposition in the LegCo, Hong Kong's parliament. After four lawmakers were ousted on a decision by the Central Government in Beijing on 11 November, the remaining democratic lawmakers collectively resigned in solidarity the same day.

Western countries started sanctions on China and Hong Kong officials and suspended agreements with Hong Kong, notably the Surrender of Fugitive Offenders.

2 November

Hong Kong Telecom staff sentenced to 2 years in prison for doxxing police officers A 33-year-old male former technician of Hong Kong Telecom, accused of obtaining personal information of police officers and their family members, and uploading some of the information to Telegram during the 2019 protests. He was sentenced to two years in prison after having been convicted in October of three "access to computer with criminal or dishonest intent" charges and one "offence for disclosing personal data obtained without consent from data users".

Hong Kong Connection journalist investigating 721 Yuen Long attack arrested

Freelance journalist Bao Choy, who filmed a Hong Kong Connection episode about the 2019 Yuen Long attack, was arrested. She was charged with misusing a government vehicle licensing database and making false statements to obtain information and records about car owners after trying to discover the owners of a few vehicles suspected of supplying weapons to the attackers. The owners of cars were identified as rural village leaders. She checked a box to declare that the vehicle registration searches were for "other traffic and transport related matters". Other options available when accessing the database were ‘legal proceedings’ and ‘sale and purchase of vehicles’. While the previously available option ‘other purposes’ had been scrapped, the magistrate said that Choy should have considered other means to obtain the information. The police dismissed allegations that the arrest was an attack on press freedom.

3 November

Canada considering large-scale evacuation Jeff Nankivell, Consul general of Canada in Hong Kong and Macau told a parliamentary committee that should the security situation in Hong Kong deteriorate, the Canadian government would offer assistance to its nearly 300,000 citizens living in Hong Kong. This, he said, would include the situation where "the urgent departure of a large number of Canadians would be necessary", the likelihood of which situation he assessed as "right now to be low". The Canadian consulate would not be able to help asylum seekers, however, which he said was in line with global policies of Canada which were "similar to most other countries" regarding applicants from their own country or territory.

4 November

Human rights lawyer Lu Siwei investigated Sichuan human rights lawyer Lu Siwei received a notification from the local justice bureau demanding that his law firm hand over all his cases for investigation. Sources said this was related to Lu's handling of the 12 Hongkongers case and that the authorities wanted to force him to quit handling the case.

HKBU student journalist charged with obstructing police officers and resisting arrest The Students' Union Editorial Board at Hong Kong Baptist University stated that one of its journalists had the previous night been formally charged with obstructing police officers and resisting arrest when interviewing at a "Lunch with you" protest in Central held on 8 May. He was to appear in court on 6 November. At the May protest, police officers thought that Tang – who according to the editorial board was wearing a press pass – looked suspicious. He was said to have ignored police requests to have his bag checked and show his identity card, and shouted emotionally (in Cantonese) "Is it illegal to take pictures?". The police asked him to stay calm, or he would be arrested for misbehavior in public places. He was arrested later. The prosecution said he had struggled fiercely when being arrested. A reporter of Hong Kong Free Press who was present at the scene heard Tang shouting that he had been beaten.

5 November

National Security Department reporting hotline launched Hong Kong police announced the launch of a National Security Department reporting hotline on their website and on their Facebook page. Citizens could make related non-urgent reports through Wechat, SMS, or email, while the phone hotline would not answer any incoming calls and replies. Lawmaker James To worried that the reporting hotline would cause distrust among people. Icarus Wong, member of the organisation "Civil Rights Observer" said the hotline might engender "a culture of retaliatory informing, Cultural Revolution style", and create a chilling effect.

CUHK alleged promotional material of its student union to be in violation of the law The CUHK students' union planned to hold an exhibition to commemorate the first anniversary of the siege of CUHK, with its promotional materials showing pictures of the siege and its poster showing photos of CUHK principal Rocky Tuan and the former principal Joseph Sung. CUHK issued a statement, accusing the protesters of "illegal use of portraits" and urging the event organiser to modify or remove the promotional materials immediately to avoid breaking the law.

6 November

Four police associations issued an open letter to CUHK President Rocky Tuan Four police associationsSuperintendents Association, Hong Kong Police Inspectors' Association, Overseas Inspectors Association, and Junior Police Associationissued an open letter to Chinese University of Hong Kong President Rocky Tuan, in which they repeated their accusations from an October 2019 letter. That month, Tuan had met with students, one of whom had accused police of sexual assaults during arrests, and had later said in an open letter that the school was in touch with 20 students regarding alleged mistreatment; he had also urged an independent probe into police action. As in their first letter, to which Tuan had not responded, police took issue with the statements from the students being, in their view, unsubstantiated and unverified. They asked Tuan to take responsibility for the escalation into the November siege of CUHK.

PolyU tightens campus security ahead of siege anniversary Hong Kong Polytechnic University announced that it would refuse entry to most visitors from 6 November. The measure came days before the first anniversary of the siege of the university in November 2019, and followed the installation of turnstiles and the requirement on campus visitors to register before arriving.

7 November

CityU, HKBU confirm tighter access control On an inquiry by HK01, CityU replied that in February 2020, the school had completed the installation of an electronic access system and enhanced security measures on the campus. Hong Kong Baptist University had undertaken similar measures.

8 November

Police raises purple banner on first anniversary of Chow Tsz-lok's death On the first anniversary of the death of 22-year-old Hong Kong University of Science and Technology student Chow Tsz-lok, a large number of citizens went to the car park in Tseung Kwan O, where Chow had sustained the injuries that led to his death, to mourn and lay flowers at night. A large number of Tactical Police officers were on guard around the road and in the parking lot, and repeatedly opened microphones to warn those present or violated the gathering restriction order, and asked citizens to leave the scene after completing their mourning. Later, the police officers claimed that they wanted to implement crowd control and set up a cordon in front of the altar for a time. At 8 pm, it was originally planned to hold a silent mourning ceremony, but after someone chanted Liberate Hong Kong, Revolution of our Times, the police officers ran across the road and raised a purple flag to warn that the slogan might violate the Hong Kong national security law.

9 November

Department of Justice appeals against acquittal of protesters accused of rioting on 31 August 2019 The Department of Justice confirmed it had filed an appeal against the acquittal of seven defendants accused of rioting on the night of 31 August 2019, and the dropping of charges against an eighth, social worker Jackie Chen, in late October 2020 and September 2020 respectively. The letter stated that the department was dissatisfied with the decision of District Court Judge Sham Siu-man, who they believed did not adequately and fully consider and analyze all the evidence.

Pro-democracy lawmakers threaten to collectively resign if four disqualified According to unconfirmed reports, the Standing Committee of the National People's Congress was to revoke the qualifications of four democratic legislators, Alvin Yeung, Dennis Kwok, Kwok Ka-ki and Kenneth Leung, during its meeting on 10 and 11 November. They would be accused of filibustering meetings and violating their oaths of office. The four legislators had been barred from running in the original September Legislative Council election which was later postponed by a year due to the COVID-19 pandemic; the four had decided to stay on for that year.

On 9 November, 19 pan-democratic lawmakers met with reporters in response to the reports, indicating that they had unanimously decided that if the four were disqualified, they would have no hesitation in resigning collectively.

U.S. imposes sanctions against Chinese and Hong Kong officials The U.S. Department of the Treasury announced sanctions against four people accused of 'involving in suppressing dissent in Hong Kong', including Li Kwai-wah, Senior Superintendent of the National Security Department of the Hong Kong Police Force, Edwina Lau, deputy director of the Police Department, Li Jiangzhou, deputy director of the National Security Agency, and deputy director of the Hong Kong and Macau Affairs Office of the State Council Deng Zhonghua. In response, Chinese Foreign Ministry spokesperson Wang Wenbin told reporters at a daily briefing that the sanctions by the United States "grossly interfere in China's internal affairs", and demanded that the sanctions be withdrawn.

Hong Kong suspends surrender of fugitive offenders and mutual legal assistance agreements with multiple countries The Hong Kong government announced that it had notified the Consulates General of the Netherlands and Ireland in Hong Kong respectively in accordance with the instructions of the Central Government to suspend the implementation of the agreement on the surrender of fugitive offenders and the agreement on criminal judicial assistance between Hong Kong and the two countries. The government also issued notices to the French, German, and Finnish consulates, shelving the surrender agreement with France, suspending the implementation of the surrendering fugitive agreement with Germany and Finland, and suspending the implementation of the criminal judicial assistance agreement between Hong Kong and the above three countries.

11 November

Four LegCo members disqualified