The context of this research contains the author's analysis of the main approaches to fixing legal principles in the normative acts of the Anglo-American system of law and the continental system of law, in particular, the principle of good faith, which is inherently associated with the idea of fair business practices, as well as the principle of bad faith, which is antagonistic to it. Scientific interest in the principle of good faith, as well as other legal principles, does not weaken due to the fact that many States, implementing the best legal practices in the legal doctrine, use the reception of law. Following the global integration processes, many States continue to adopt various legal institutions and concepts in the countries of continental law and Anglo-Saxon law. And being a party to many international conventions, they do so for reasons of expediency, enriching domestic law enforcement practice.