»Sustainability Obligations in the Light of Entrepreneurial Freedom«: This analysis begins by examining the conceptual foundations of sustainability and the relevant legal frameworks. It then outlines cross-sector sustainability obligations that companies are increasingly subject to. These obligations are critically assessed against the yardstick of constitutionally protected entrepreneurial freedom rights. The findings indicate that certain regulatory measures adopted under the banner of sustainability may conflict with European Union an constitutional law. The effects of these obligations on companies are analysed on the basis of an empirical survey.