Foreign lawyers [assumming foreign-owned law firms too] are only allowed to provide legal services in Cambodia in "commercial association" with Cambodian lawyers. Foreign lawyers may not directly represent clients in courts [assuming possible in association with a Cambodian lawyer as per above]. Foreign lawyers may only practice their profession in the territory of the Kingdom of Cambodia with authorisation from the Khmer Bar Council; this authorisation is subject to reciprocity.
"Art. 1. The legal profession is an independent and autonomous profession involved in serving justice and may only be pursued from within the framework of the Bar Association.
[...]
Art 4. Apart from those lawyers who are members of the Bar Association, no one may perform this profession or provide legal consultation or prepare judicial documents for compensation, except when such legal consultation or preparation of documents is a ancillary job to their profession or is a function permitted by the law.
Art 5. Foreign lawyers whose names have been registered by the Bar of a foreign country or who have been recognized and authorized by the countries of their origin to practice the legal profession have the right to practice the profession with a Khmer lawyer and accompany/assist Khmer lawyers before the courts or other institutions of the Kingdom of Cambodia. Foreign lawyers may not represent (stand in for) clients.
Art. 6. Foreign lawyers may only practice their profession in the territory of the Kingdom of Cambodia with authorization from the Khmer Bar Council; this authorization will depend on the sufficiency of qualifications of the foreign lawyer and will only be granted when the country of origin of the foreign lawyer provides this same possibility to Cambodian lawyers.
[...]
Art. 7. Those foreign lawyers who have been authorized to practice this profession may not perform any activity to attract clients or do any commercial advertising.
[...]
SECTION 1: CONDITIONS
Art. 31. A person may engage in the profession as a lawyer, provided that he or she has fulfilled the conditions hereunder:
1. Shall have Khmer nationality
[...]
CHAPTER FOUR: PROCEDURES FOR PROFESSIONAL PRACTICE
SECTION 1: THE PRACTICE OF LAW INDIVIDUALLY OR COLLECTIVELY
Art. 46. Lawyers may practice their profession individually or within the context of a group or a Law Firm which is lawfully established.
This Firm must have a character of a civil company in which all of its members are lawyers.
An Honorary Lawyer may remain as a member of his or her original Firm.[...]" (Law on the Bar, of 15 June 1995, Art. 1, 4-7, 31, 46)
Law on the Bar, of 15 June 1995, Art. 1, 4-7, 31 and 46.
[<a href="https://www.wto.org/english/thewto_e/acc_e/khm_e/WTACCKHM3A3_LEG_50.pdf">Law</a>]