The public good was one of the key concepts of Enlightenment political discourse, although its content eluded precise definitions, being lost between the “common good”, interpreted from Christian and moral perspectives, and the “common interest” underlying the social contract. Most philosophers and writers of the eighteenth century regarded it as a field of action of the sovereign, as a sovereign's duty, and only Montesquieu connected it with reflections on the republican structure of the state rather than with the image of an idealised monarchy, transforming the idea of the public good into the principle of collective virtue, which is the basis of citizens' unity and the sphere of their collective responsibility. The public good turned out to be one of the most important concepts in the legislative vocabulary of Catherine II, along with the concepts of the Fatherland and patriotism, with which it was closely connected. The empress actively introduced it into the Russian political discourse. However, the analysis in this article of the preambles to the laws accompanying her administrative, economic or educational reforms allows one to see that in her interpretation the public good was systematically identified with the personal interests of the sovereign and was easily confused with state interests. The author suggests that Catherine II, who considered herself to be Montesquieu's disciple, did not adopt the approach proposed by her mentor in “De l'esprit des lois”, an approach that viewed the public good as a political virtue and a sphere of collective responsibility of citizens, remaining within the old paradigm that treated the public good as a duty of the sovereign and as a favour he bestows on his subjects.