Only locally licensed lawyers can be partners in a law firm. Since 2019, Slovenian/EU/EEA/Swiss citizenship is required to become a licensed lawyer; previously, only citizens of Slovenia could become licensed lawyers. Foreign licensed lawyers from third (non-EU) countries may exercise only subject to material reciprocity. 
"Article 2
As part of the practice of the legal profession, a lawyer provides legal advice, represents and defends clients before courts and other state bodies, draws up documents and represents clients in their legal relations.
Only a lawyer may represent a party against payment in court, unless otherwise provided by law.
Article 2a
A foreign lawyer who has acquired the right to practice law in his home country may, under the conditions determined by this Act, practice in the Republic of Slovenia:
- legal services under professional title from their home country in accordance with Directive 77/249 / EEC,
- the legal profession under the professional title of his home country in accordance with Directive 98/5 / EC,
- the legal profession called "lawyer".
Home is the country in which a lawyer has the right to practice law under a professional title obtained in accordance with the regulations of that country.
Under this Act, a lawyer from another country which is a Member State of the European Union, the European Economic Area or the Swiss Confederation is a lawyer entitled to practice law in any Member State of the European Union, the European Economic Area or the Swiss Confederation under a professional title under the regulations of that country.
[...]
Article 25
A lawyer can be someone who meets the following conditions:
1. that he is a citizen of the Republic of Slovenia, another Member State of the European Union, the European Economic Area or the Swiss Confederation, [...]
A foreign citizen who meets the conditions for practicing law under the law of the country of which he is a citizen shall, if reciprocity apply, enter himself in the register of lawyers who may practice law before state bodies in the Republic of Slovenia:
1. if he passes the mock exam on knowledge of the legal order of the Republic of Slovenia according to a special law,
2. (deleted)
3. (deleted).
[...]
Article 34f
A lawyer from another country other than a Member State of the European Union, the European Economic Area or the Swiss Confederation who has the right to practice law in a country not a member of the European Union, the European Economic Area or the Swiss Confederation may practice law or practice under the conditions, which are determined by this Act for lawyers from another country, which is a Member State of the European Union, the European Economic Area or the Swiss Confederation, in Article 34.a of this Act, if the condition of actual reciprocity is met.
[...]
Article 37
The activity of a law firm is limited to the practice of the legal profession.
The amalgamation of law firms for the purpose of joint practice of law is not permitted.
The partners of a law firm may only be lawyers who practice law in a law firm. Partners may not practice law in other law firms.
The management of a law firm cannot be entrusted to a person who is not a lawyer.
A limited liability law firm must have an office at its registered office in which at least one partner practices law.
The law firm is obliged to notify the Bar Association of Slovenia of any change in the articles of association, the partner or the person authorized to represent, as well as the establishment or termination of the branch.[...]" (Law on Advocacy (Official Gazette of the Republic of Slovenia, nos. 18/93), last amended on 7 June 2019, Articles 2, 2a, 25, 34f and 37 [google translation])
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"Article 25
Anyone who meets the following conditions can be a lawyer:
1. that he is a citizen of the Republic of Slovenia,
2. that he is commercially fit,
3. that he has obtained the following professional title in the Republic of Slovenia or has completed an equivalent education abroad, recognized in accordance with the law governing the recognition and evaluation of education:
- professional title university graduate in law,
- professional titles Bachelor of Laws (UN) and Master of Laws,
- the professional title of Master of Law based on a single master's study program,
4. that he passed the legal state exam,
5. that he has four years of practical experience as a university graduate in law, of which at least one year after passing the state legal exam at a lawyer or law firm, in a court, state prosecutor's office, state attorney's office or notary, in a regular employment relationship concluded with an employment contract full-time,
6. to actively master the Slovenian language,
7. that he is trustworthy for practicing the legal profession,
8. that it has equipment and premises that are necessary and suitable for practicing the legal profession.
9. that he has passed the knowledge test of the law governing the profession of lawyer, lawyers' tariffs and the Code of Professional Ethics of Lawyers at the Bar Association of Slovenia.
The content and procedure of the test referred to in point 9 of the previous paragraph shall be prescribed by the minister responsible for justice. The Bar Association of Slovenia can give an opinion on the content and procedure of the test beforehand, within 30 days of receiving the notification." (Law on Advocacy (Official Gazette of the Republic of Slovenia, nos. 18/93), last amended on 30 June 2016, Article 25 [google translation])
Law on Advocacy (Official Gazette of the Republic of Slovenia, nos. 18/93), last amended on 7 June 2019, Articles 2, 2a, 25, 34f and 37
Law on Advocacy (Official Gazette of the Republic of Slovenia, nos. 18/93), last amended on 30 June 2016, Article 25
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