Background: Since the 1960s, the notion of sustainability has gained worldwide significance, including environmental issues, and advocating for sustainable economic development. Businesses have a crucial role in reducing environmental effects, motivated by pressure from stakeholders such as governments and shareholders. While environmental and economic sustainability receive significant attention, the social aspect often receives less attention. Social sustainability involves creating equitable social systems and ensuring ethical practices, employee well-being, and diversity. Sustainability Consultancy Companies (SCCs) assist firms in integrating sustainability into their daily operations. Nevertheless, SCCs must comply with social sustainability principles, ensuring that they implement the same values they advocate for to maintain their reputation and establish industry benchmarks.   Purpose: The purpose of this research is to determine the extent to which Sustainability Consulting Companies (SCCs) are implementing sustainable practices within their daily operations.  We are investigating whether SCCs possess the necessary knowledge, expertise, and in-depth understanding of issues related to social sustainability practices. Our research aims to provide practitioners with knowledge and awareness of how SCCs perceive social sustainability and to what extent they implement social sustainability practices.    Method: This thesis employed a qualitative research approach, incorporating relevant literature, peer-reviewed articles, and semi-structured interviews. Through the semi-structured interviews conducted with various Sustainability Consultancy Companies (SCCs), employees, and a CEO, we were able to gather varying perspectives and professional insights on social sustainability issues.   Conclusion: The findings of this research indicate that although most SCCs had knowledge on social sustainability issues and practices, only a limited number of levels in Carroll’s CSR Pyramid were fulfilled. Furthermore, while the SCCs consider social sustainability as the missing pillar, there is a limited focus on implementing social sustainability in comparison to the other pillars of sustainability.