The Regional Flag of the Hong Kong Special Administrative Region of the People's Republic of China depicts a white stylised five-petal Hong Kong orchid tree (Bauhinia × blakeana) flower in the centre of a Chinese red field. The design of the flag is enshrined in Hong Kong Basic Law, the territory's constitutional document, and regulations regarding its use, prohibition of use, desecration, and manufacture are stated in the Regional Flag and Regional Emblem Ordinance.
The original design of the flag of Hong Kong was unveiled on 4 April 1990 at the Third Session of the Seventh National People's Congress. The current design was approved on 10 August 1996 at the Fourth Plenum of the Preparatory Committee of the Hong Kong Special Administrative Region. The use of the flag is regulated by laws passed by the 58th executive meeting of the State Council held in Beijing. The flag was officially adopted and hoisted on 1 July 1997, during the handover ceremony marking the handover from the United Kingdom back to China.
A variant of the flag known as the Black Bauhinia has been used by anti-Chinese government protesters in Hong Kong, particularly during the 2019–2020 Hong Kong protests. In contrast of the protests, pro-government supporters often display the Chinese and Hong Kong flags.
The design of the flag comes with cultural, political, and regional meanings. The colour itself is significant; red is a festive colour for the Chinese people, used to convey a sense of celebration and nationalism. Moreover, the red colour is identical to that used in the national flag of the People's Republic of China, chosen to signify the link re-established between post-colonial Hong Kong and mainland China. The position of red and white on the flag symbolises the "one country, two systems" political principle applied to the region. The stylised rendering of the Bauhinia × blakeana flower, a flower discovered in Hong Kong, is meant to serve as a harmonising symbol for this dichotomy. The five stars of the Chinese national flag are replicated on the petals of the flower. The Chinese name of Bauhinia × blakeana is most commonly rendered as yángzǐjīng (洋紫荊), but is often shortened to zǐjīng (紫荊/紫荆) in official uses since yáng (洋) means "foreign" in Chinese, notwithstanding that the shortened name refers to another genus, Cercis. A sculpture of the plant has been erected in Golden Bauhinia Square in Hong Kong.
Before the adoption of the flag, Ji Pengfei, the Chairman of the Hong Kong Basic Law Drafting Committee explained the significance of the flag's design to the National People's Congress:
The regional flag carries a design of five bauhinia petals, each with a star in the middle, on a red background. The red flag represents the motherland and the bauhinia represents Hong Kong. The design implies that Hong Kong is an inalienable part of China and prospers in the embrace of the motherland. The five stars on the flower symbolise the fact that all Hong Kong compatriots love their motherland, while the red and white colours embody the principle of "one country, two systems".
The Hong Kong government has specified sizes, colours, and manufacturing parameters in which the flag is to be made. The ratio of its length to breadth is 3:2. In its centre is a five-petal stylised rendering of a white Bauhinia × blakeana flower. If a circle was to circumscribe the flower, it would have a diameter 0.6 times the entire height of the flag. The petals are uniformly spread around the centre point of the flag, radiating outward and turning in a clockwise direction. Each of the flower's petals bears a five-pointed red star with a red trace, suggestive of a flower stamen. The heading that is used to allow a flag to be slid or raised onto a pole is white.
A slightly different geometrical description of the flag is specified in the mandatory National Standard "GB 16689-2004: Regional flag of Hong Kong special administrative region".
This table lists all the official sizes for the flag. Sizes deviating from this list are considered non-standard. If a flag is not of official size, it must be a scaled-down or scaled-up version of one of the official sizes.
The Regional Flag and Regional Emblem Ordinance stipulates that "The regional flag is in red, the chrominance value of which is identical with that of the national flag of the People's Republic of China," and that the emblem is white.
The Regional Flag and Regional Emblem Ordinance stipulates that the Hong Kong flag must be manufactured according to specifications laid out in the ordinance. If flags are not produced in design according to the ordinance, the Secretary for Justice may petition the District Court for an injunction to prohibit the person or company from manufacturing the flags. If the District Court agrees that the flags are not in compliance, it may issue an injunction and order that the flags and the materials that were used to make the flags to be seized by the government.
The Hong Kong flag is flown daily from the chief executive's official residence (Government House), at the Hong Kong International Airport, and at all border crossings and points of entry into Hong Kong. At major government offices and buildings, such as the Office of the Chief Executive, the Executive Council, the Court of Final Appeal, the High Court, the Legislative Council, and the Hong Kong Economic and Trade Offices overseas, the flag is displayed during days when these offices are working. Other government offices and buildings, such as hospitals, schools, departmental headquarters, sports grounds, and cultural venues, should fly the flag on occasions such as the National Day of the People's Republic of China (1 October), the Hong Kong Special Administrative Region Establishment Day (1 July), and New Year's Day. The flag should be raised at 8:00 a.m. and lowered at 6:00 p.m. The raising and lowering of the flag should be done slowly; it must reach the peak of the flagstaff when raised, and it may not touch the ground when lowered. The flag may not be raised in severe weather conditions. A Hong Kong flag that is either damaged, defaced, faded or substandard must not be displayed or used.
Whenever the Chinese national flag is flown together with the Hong Kong regional flag, the national flag must be flown at the centre, above the regional flag, or otherwise in a more prominent position than that of the regional flag. The regional flag must be smaller in size than the national flag, and it must be displayed to the left of the national flag. When the flags are displayed inside a building, the left and right sides of a person looking at the flags, and with his or her back toward the wall, are used as reference points for the left and right sides of a flag. When the flags are displayed outside a building, the left and right sides of a person standing in front of the building and looking towards the front entrance are used as reference points for the left and right sides of a flag. The national flag should be raised before the regional flag is raised, and it should be lowered after the regional flag is lowered.
The Hong Kong flag must be lowered to half-mast as a token of mourning when any of the following people die:
President of the People's Republic of China
Chairman of the Standing Committee of the National People's Congress
Chairman of the Central Military Commission
Chairman of the National Committee of the Chinese People's Political Consultative Conference