The Norwegian regulation of Related Parties Transactions (RPT) has been developed through a total of five phases. The development startet with the EEA-adaption of the former Limited Liability Act of 1976 in 1995. Originally, a rule on «Nachgrundung» in public limited companies was enacted. The General Assembley had to approve specified agreements for them to be valid. The statutory provision largely coincided with the requirements of the EU’s Second Company Law Directive. With The Limited Companies Acts of 1997 the rule was significantly extended to include agreements on both limited companies’ and public limited companies’ acquisitions from shareholders as well as from natural and legal persons treated as shareholders. The provisions made exceptions for, amongst others, commercial agreements. Later the provision was extended to cover all types of agreements (acquisitions as well as disposals, etc.) with an expanding circle of natural and legal persons. Attempts were made to precisely define the exception for commercial agreements and additional exceptions were introduced. By amendments in 2019, the Public Limited Companies Act was adapted to the requirements of SRD II. For limited liability companies and for non-listed public limited companies substantial amendments were enacted. The number of agreements that should apply with the procedural rules was in reality significantly reduced, attempts were made to further specify the exception for commercial agreements, the necessary resolutions shall be made by the Board of Directors and not any longer by the General Assembley, and the invalidity rule was softended. The paper reviews the development of the Norwegian rules on RPTs and the circumstances leading to the various amendments of these rules. Furthermore, it includes an analysis of the new rules on RPTs applicable to limited companies and non-listed public limited companies.