<p>Ethical organizational climate is a pivotal topic in business ethics, influencing employees’ well-being and attitude toward the organization. In Poland, there is a lack of measures dedicated to verifying organizational climate. Our research aimed to examine the psychometrical properties of the Ethical Climate Questionnaire (ECQ) in Polish business conditions. Studies conducted on two samples confirmed the original structure of the Polish version of the ECQ and its better psychometric properties compared to the original version. Confirmatory factor analysis (CFA) confirmed good construct validity and internal consistency of the ECQ, with Cronbach’s alpha coefficients in the range of 0.74–0.81, depending on the type of ethical climate. Bagozzi and Heatherton’s criteria of the magnitude of factor loadings, average variance extracted, and composite reliability showed good convergent validity of the tool. The value of the heterotrait–monotrait ratio of correlations indicated good discriminant validity of the ECQ. Also, the criterion validity of this measure was confirmed. In conclusion, the Polish version of the ECQ is a measure that can be used to study the ethical climate in Polish organizations.</p>