The article emphasizes the underlying problem of good faith in business law. This is a crucial topic widely discussed in the EU, but implementation of common tools is limited. Business practices in the Czech Republic were under the pressure of socialism for more than 40 years; therefore, Czech business culture has not been cultivated enough since the First Republic. The current tendencies in the decisions of Czech courts show a shift in the right direction. An analysis of legal regulations of good faith in different EU countries gives an overview of common similarities and differences.