The sustainable development challenge is increasingly being included in entrepreneurs’ agendas. Firms are considered responsible for social and environmental effects but are also considered social actors that can effectively incorporate sustainability solutions into market transactions. The literature on corporate social responsibility (CSR) in small and medium business (SMEs) has depicted these firms as less involved in sustainability management implementation, due to resource constraints and limited perception of the business case for sustainability. The paper analyses factors influencing sustainability practices implementation: (1) pressures from external environment, (2) expected benefits of sustainability implementation and (3) entrepreneur’s inner features in guiding strategy practices implementation. With these premises, the paper aims to identify the main drivers or barriers of sustainability implementation and to verify any significant differences between small and large-sized companies in their approach to sustainability. The findings highlight the existence of some common features among small and large firms, in particular regarding motivations, entrepreneur values, and business vision. Studies on both small business have highlighted the pivotal role of entrepreneurs’ values in motivating a more sustainable way of conducting business while large companies, driven by external pressures, are more focused on a strategic CSR approach than small firms.
