Foreign law firms established in Viet Nam (i.e. branches, subsidiaries and JV with Vietnamese law firms) are allowed to counsel on Vietnamese law if this is performed by a licensed Vietnamese lawyer, but are not not allowed to represent clients in courts. There are no restrictions to counselling on international and/or foreign law.
"Article 3. Definitions
For the purposes of this Law, the terms below are construed as follows: [...]
10. “market access conditions applied to foreign investors” mean those which must be satisfied by foreign investors to make investment in the List of business lines with prohibited and restricted market access (hereinafter referred to as “the Negative List for Market Access”) specified in Clause 2 Article 9 of this Law.  [...]
19. “foreign investor” means an individual holding a foreign nationality or an organization established under foreign laws and carrying our business investment activities in Vietnam.
20. “domestic investor” means an individual holding Vietnamese nationality or a business organization whose members or shareholders are not foreign investors. 
[...]
Article 4. Application of the Law on Investment and relevant laws
1. Business investment activities in the territory of Vietnam [must] comply with the Law on investment [this Law] and other relevant laws.
2. If there is any discrepancy between the provisions of this Law and those of another law issued before the effective date of this Law in relation to the industries and trades in which business investment is prohibited, or industries and trades in which business investment is conditional, then the provisions of the Law on investment [this Law] shall prevail.
[...]
Article 9. Business lines with prohibited and restricted market access and market access conditions applied to foreign investors
1. Market access conditions applied to foreign investors are the same as those applied to domestic investors, except for the case specified in Clause 2 of this Article.
2. Pursuant to Laws and Resolutions of the National Assembly, Ordinances and Resolutions of the Standing Committee of the National Assembly, Decrees of the Government and international treaties to which the Socialist Republic of Vietnam is a signatory, the Government shall promulgate a Negative List for Market Access, including:
a/ Prohibited business lines; b/ Restricted business lines.
3. Market access conditions applied to foreign investors specified in the Negative List for Market Access include:
a/ Holding of charter capital by the foreign investor in a business organization; b/ Investment method; c/ Scope of investment; d/ Capacity of the investor; partners participating in the investment activities; dd) Other conditions specified in the Laws and Resolutions of the National Assembly, Ordinances and Resolutions of the Standing Committee of the National Assembly, Decrees of the Government and international treaties to which the Socialist Republic of Vietnam is a signatory.
[...]
Article 23. Implementation of investment activities by foreign-invested economic organizations
1. When making investment in establishment of other economic organizations; contribution of capital to, or purchase of shares or capital contributions at, other economic organizations; or investment in the form of BCC, economic organizations must meet the conditions and shall carry out investment procedures according to regulations applicable to foreign investors if falling into one of the following cases:
a/ Having over 50% of their charter capital held by a foreign investor/foreign investors, or having a majority of their general partners being foreign individuals, for partnerships;
b/ Having over 50% of their charter capital held by an economic organization/economic organizations specified at Point a of this Clause;
c/ Having over 50% of their charter capital held by a foreign investor/foreign investors and an economic organization/economic organizations specified at Point a of this Clause. [...]" (Law on Investment No. 61/2020/QH14 of 17 June 2020 [google translation])
------------------------------------
"Section 2. SECTORS, LINES AND MARKET ACCESS CONDITIONS FOR FOREIGN INVESTORS
Article 15. Sectors and trades restricted from market access for foreign investors
1. Sectors and trades with restrictions on market access for foreign investors and restrictions on market access for such industries and trades are prescribed in laws and resolutions of the National Assembly, ordinances and resolutions. of the National Assembly Standing Committee, Government decrees and international treaties on investment. The list of industries and trades with restrictions on market access for foreign investors is published in Appendix I of this Decree.
2. Market access conditions for foreign investors shall be applied in the forms specified in Clause 3, Article 9 of the Law on Investment and posted and updated according to the provisions of Article 18 of this Decree.
[...]
Article 16. Subjects of application of the List of industries and trades restricted from market access
1. The list of industries and trades with restricted market access applies to:
a) Foreign investors as prescribed in Clause 19, Article 3 of the Law on Investment ;
b) The economic organization specified at Points a, b and c, Clause 1, Article 23 of the Law on Investment when investing in the establishment of other economic organizations; make capital contribution, purchase shares, purchase capital contribution portion of other economic organizations; investment in the form of BCC contract.
(In this Section, the subjects specified at Points a and b of this Clause, hereinafter collectively referred to as foreign investors, unless otherwise provided for by this Decree).
[...]
Article 17. Principles of applying restrictions on market access for foreign investors
1. Except for the industries and trades on the List of industries and trades with restricted market access for foreign investors specified in Appendix I of this Decree, foreign investors are entitled to market access as prescribed for domestic investors.
2. Foreign investors are not allowed to invest in industries and trades that have not yet been able to access the market as prescribed in Section A, Appendix I of this Decree.
3. For industries and trades with conditional market access for foreign investors as prescribed in Section B, Appendix I of this Decree, foreign investors must satisfy the conditions for market access according to the provisions of Article 18 of this Decree.
4. Market access conditions for industries and trades that Vietnam has not yet committed to market access to for foreign investors are applied as follows:
a) Where laws and resolutions of the National Assembly, ordinances and resolutions of the National Assembly Standing Committee, decrees of the Government (hereinafter referred to as Vietnamese law) do not contain provisions restricting access to the market for that industry or trade, foreign investors may access the market as prescribed for domestic investors;
b) Where Vietnamese law already contains provisions on restricting foreign investors' market access for such industries or trades, the provisions of Vietnamese law shall apply. [...]
7. Foreign investors belonging to countries or territories that are not members of the WTO and conducting investment activities in Vietnam are entitled to the same market access conditions as those applicable to national investors. a territory that is a member of the WTO, unless otherwise provided for by Vietnamese law or an international treaty between Vietnam and that country or territory.
[...]
B. BUSINESS LINES WITH RESTRICTED MARKET ACCESS [...]
20. Legal services [...]"(Government Decree on the Elaboration of Some Articles of the Law on Investment No. 31/2021/ND-CP of 26 March 2021 [google translation] (Decree 31), which provides guidance on the implementation of the new Law on Investment [google translation])
---------------------------
"INDUSTRY, SECTOR | CONDITIONS LIMITED MARKET ACCESS | LEGAL BASIS [not reproduced here] [...]
20. Legal services
1. Provisions in the Agreements:
Legal services (CPC 861, excluding: participating in legal proceedings as a defense counsel or representing their clients before the Vietnamese Courts; legal document services and notarization related to the law). Law of Vietnam): A foreign lawyer's organization[1] is permitted to establish a commercial presence in Vietnam in the following forms:
- Branches of foreign lawyers' organizations.
- Subsidiaries of foreign law organizations.
- Foreign law firms[2].
- A partnership between a foreign law firm and a Vietnamese law partnership.
The commercial presence of a foreign lawyer organization is allowed to provide Vietnamese law advice if the consulting lawyer has graduated from a Vietnamese law university and meets the requirements applicable to similar Vietnamese lawyers. 
2. Vietnamese law
- Commit and ensure that at least two foreign lawyers, including the head of a branch or the director of a foreign law firm, are present and practice in Vietnam for 183 days or more in a consecutive twelve-month period. (Clause 2, Article 68 of Law amending Law on Lawyers 2012)
- Scope of operation of a foreign law-practicing organization related to intellectual property: "Not allowed to provide industrial property representation services, plant variety rights representation services, plant variety supervision services, etc. intellectual property regulations”.
[1] “Foreign lawyer organization” means an organization of practicing lawyers established in a foreign country by one or more lawyers or law firms in any form of commercial company (including law firm, limited liability law firm, joint stock law firm, etc.).
[2] Foreign law firm is an organization established in Vietnam by one or more foreign law organizations for the purpose of practicing law in Vietnam. [...]" (Government of Viet Nam, List B: List of occupations with conditional market access for foreign investors: Conditions (updated 2020), webpage [google translation])
---------------------------
"Article 68. Practice conditions of foreign law-practicing organizations
A foreign law-practicing organization that has been established and is lawfully practicing law in a foreign country may practice law in Vietnam in accordance with this Law when fully meeting the following conditions:
1. Commit and ensure compliance with the Constitution and laws of the Socialist Republic of Vietnam;
2. Commit and ensure that at least two foreign lawyers, including the head of a branch or the director of a foreign law firm, are present and practice in Vietnam for 183 days or more in a twelve consecutive period. month;
3. Heads of branches and directors of foreign law firms in Vietnam must have at least two consecutive years of practicing law.
Article 69. Practice forms of foreign law-practicing organizations
1. Foreign law-practicing organizations practice in Vietnam in the following forms:
a) Branches of foreign law-practicing organizations (hereinafter referred to as branches);
b) One hundred percent foreign owned limited liability law firms, limited liability law firms in the form of joint ventures, law partnerships between a foreign law-practicing organization and a partnership law firm. Vietnam (hereinafter referred to as foreign law firms).
2. Foreign branches and law firms may be organized and operate in accordance with this Law, the law on enterprises, the law on investment and other relevant laws. 
[...]
Article 70. Scope of practice of foreign lawyers' organizations
Branches of and foreign lawyer practicing organizations in Vietnam may provide legal consulting services and other services, but shall not have their foreign lawyers and Vietnamese lawyers to participate in legal proceedings in the capacity of representatives, defenders or protectors of rights and benefits of the main parties before the courts of Vietnam nor provide legal documentation and certification services related to the laws of Vietnam, [branches of and foreign lawyer practicing organizations] may have their Vietnamese lawyers to provide legal consultancy on the laws of Vietnam.[...]
Article 76. Scope of practice of foreign lawyers
Foreign lawyers practicing in Vietnam are entitled to foreign and international law advice, to provide other legal services related to foreign laws, and to be consulted on Vietnamese laws in case there is a problem. A bachelor's degree in Vietnamese law and fully meeting the same requirements as for a Vietnamese lawyer, may not participate in the proceedings as a representative, defense counsel, defender of rights and interests. legitimate interests of the involved parties before the Vietnamese Court. [...]" (Law 20/2012/QH13 Amending and supplementing a number of articles of the Law on Lawyers [google translation])
Law on Investment No. 61/2020/QH14 of 17 June 2020 [google translation]
Government Decree on the Elaboration of Some Articles of the Law on Investment No. 31/2021/ND-CP of 26 March 2021 [google translation]
Government of Viet Nam, List B: List of occupations with conditional market access for foreign investors: Conditions (updated 2020), webpage [google translation]
Law 20/2012/QH13 Amending and supplementing a number of articles of the Law on Lawyers [google translation]
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