Background and Aim: The code of ethics is constantly being reviewed, due to some changes in the professional fields of psychologists and the needs of their target groups. Conducting comparative studies creates sensibilities in experts to meet the challenges of the code of ethics. Therefore, the aim of this study is to compare the code of ethics of psychologists in Iran with the Netherlands and Switzerland's. Materials and Methods: The present study is comparative study. Using Science Direct, Pubmed and Google Scholar databases between 2000 and 2019, the keywords of code of ethics, psychology, Iran, Netherlands and Switzerland and their Persian equivalents were searched separately and in combination. The code of ethics of the Netherlands and Switzerland were purposefully selected based on the research gaps in this field; it was also structurally and contently examined, as a basis for comparison, by the Iranian code of ethics. Findings: Structurally, all three codes of ethics have common ground in the introduction and basic principles, but Switzerland and Netherlands ' codes of ethics differ in the code of conduct. In terms of content, Switzerland and Netherlands' codes of ethics are based on clear, definite and operational codes. In addition, they have adapted to the new conditions more than the Iranian code of ethics, especially in the codes related to advertising and resolving ethical issues and they have been able to create organizational and administrative structures. Ethical Considerations: Honesty and fidelity were considered in the reporting of the texts, citing sources and avoiding any bias. Conclusion: By making new changes in the Iranian code of ethics, especially in the field of clarifying the concepts and basic principles of ethics, as well as providing accurate ethical codes, taking into account the practical aspects and the method of their implementation, some challenges can be addressed. Cite this article as: Nazari E, Saed O. Professional Code of Ethics of Psychologists in Iran, Netherlands and ...