Internet censorship in Vietnam prevents access to websites critical of the Vietnamese government, expatriate political parties, and international human rights organizations, among others or anything the Vietnamese government does not agree with. Online police reportedly monitor Internet cafes and cyber dissidents have been imprisoned. Vietnam regulates its citizens' Internet access using both legal and technical means. The government's efforts to regulate, monitor, and provide oversight regarding Internet use has been referred to as a "Bamboo Firewall". However, citizens can usually view, comment and express their opinions civilly on the internet, as long as it does not evoke anti-government movement, political coup and disrupt the social stability of the country.
The OpenNet Initiative classified the level of filtering in Vietnam as pervasive in the political, as substantial in the Internet tools, and as selective in the social and conflict/security areas in 2011, while Reporters without Borders consider Vietnam an "internet enemy".
While the government of Vietnam claims to safeguard the country against obscene or sexually explicit content through its blocking efforts, many of the filtered sites contain no such content, but rather politically or religiously critical materials that might undermine the Communist Party and the stability of its one-party rule. Amnesty International reported many instances of Internet activists being arrested for their online activities.
Vietnam's internet regulation commenced in large part as a result of the government's 1997 decree concerning Internet usage, wherein the General Director of the Postal Bureau (DGPT) was granted exclusive regulatory oversight of the Internet. As a result, the DGPT regulated every aspect of the Internet, including the registration and creation of Internet Service Providers, and the registration of individuals wishing to use the Internet through subscription contracts.
Regulatory responsibility for Internet material is divided along subject-matter lines with the Ministry of Culture and Information focusing on sexually explicit, superstitious, or violent content, while the Ministry of Public Security monitors politically sensitive content. Vietnam nominally guarantees freedom of speech, of the press, and of assembly through constitutional provisions, but state security laws and other regulations reduce or eliminate these formal protections in practice. All information stored on, sent over, or retrieved from the Internet must comply with Vietnam's Press Law, Publication Law, and other laws, including state secrets and intellectual property protections. All domestic and foreign individuals and organizations involved in Internet activity in Vietnam are legally responsible for content created, disseminated, and stored. It is unlawful to use Internet resources or host material that opposes the state; destabilizes Vietnam's security, economy, or social order; incites opposition to the state; discloses state secrets; infringes organizations’ or individuals’ rights; or interferes with the state's Domain Name System (DNS) servers. Law on Information Technology was enacted in June 2006. Those who violate Internet use rules are subject to a range of penalties, from fines to criminal liability for offenses such as causing chaos or security disorder.
A 2010 law required public Internet providers, such as Internet cafes, hotels, and businesses providing free Wi-Fi, to install software to track users' activities.
In September 2013, Decree 72 came into effect; making it illegal to distribute any materials online that "harms national security” or “opposes" the government, only allows users to "provide or exchange personal information" through blogs and social media outlets—banning the distribution of "general information" or any information from a media outlet (including state-owned outlets), and requires that foreign web companies operate servers domestically if they target users in Vietnam.
OpenNet research found that blocking is concentrated on websites with contents about overseas political opposition, overseas and independent media, human rights, and religious topics. Proxies and circumvention tools, which are illegal to use, are also frequently blocked.
The majority of blocked websites are specific to Vietnam: those written in Vietnamese or dealing with issues related to Vietnam. Sites not specifically related to Vietnam or only written in English are rarely blocked. For example, the Vietnamese-language version of the website for Radio Free Asia was blocked by both tested ISPs while the English-language version was only blocked by one. While only the website for the human rights organization Human Rights Watch was blocked in the tested list of global human rights sites, many Vietnamese-language sites only tangentially or indirectly critical of the government were blocked as well as sites strongly critical of the government.
The website of the British Broadcasting Corporation (www.bbc.co.uk), which has a significant journalistic presence, is an example of a website that is blocked—albeit intermittently.
Although "obscene" content is one of the main reasons cited by the government to censor the Internet, in fact very few websites with pornography are censored in Vietnam. This shows that censorship is in fact not for government reasons. A study by OpenNet in 2006 showed that no websites with pornography were blocked (except for a site containing a link to a pornography site, but was blocked for other reasons). When some sites such as Facebook and YouTube are considered by the media representatives in Vietnam to be blocked due to economic reasons because accounting for 70%–80% of international bandwidth runs through without bringing profits to the home. At the same time, some local feedback asked if thousands of porn websites were profitable for the network without being blocked. In November 2019, some Vietnamese ISPs may have blocked a mass of porn sites silently or officially; this action hasn't been clearly announced yet.
The popular social networking website Facebook has about 8.5 million users in Vietnam and its user base has been growing quickly after the website added a Vietnamese-language interface. During the week of November 16, 2009, Vietnamese Facebook users reported being unable to access the website. Access had been intermittent in the previous weeks, and there were reports of technicians ordered by the government to block access to Facebook.
A supposedly official decree dated August 27, 2009, was earlier leaked on the Internet, but its authenticity has not been confirmed. The Vietnamese government denied deliberately blocking access to Facebook, and the Internet service provider FPT said that it is working with foreign companies to solve a fault blocking to Facebook's servers in the United States.
In Vietnam, Yahoo! 360° was a popular blogging service. After the government crackdown on journalists reporting on corruption in mid-2008, many blogs covered the events, often criticizing the government action. In response, the Ministry of Information proposed new rules that would restrict blogs to personal matters.
Global Voices Advocacy maintains a list of bloggers who have been arrested for their views expressed online. Many bloggers were arrested by the Vietnamese government during the 2011 crackdown on Vietnamese youth activists.
In 2020, Medium was blocked. As of 2021, there are still a number of Internet service provider blocks based on technology deep packet inspection.
Yahoo! Messenger is amongst the instant messaging software that appears to be monitored, with messages often blocked (i.e., not seen by intended recipient).
In 2019, Vietnam introduced a cybersecurity law that made it illegal to criticize the government online and requires ISPs to hand over user data when requested.
A component of Vietnam's strategy to control the Internet consists of the arrest of bloggers, netizens and journalists. The goal of these arrests is to prevent dissidents from pursuing their activities, and to persuade others to practice self-censorship. Vietnam is the world's second largest prison for netizens after China.