Background: Sustainability is the need of the time, everyone in the society should play a role in making a more sustainable environment. Organizations as demanded by the whole society need to be more sustainable in order to achieve survival and success. The sustainable development of a company is inseparable from a sustainable supply management. Supplier development is one of the critical parts in supply management which can contribute to the buying firm and its suppliers’ sustainable development. With different strategies in supplier development life-cycle stages and the sustainability considerations in supplier development practices are significant in corporate sustainable development. Purpose: The intention of this thesis is to empirically study what strategies in supplier development practices are implemented in Ericsson and how sustainability is taken into consideration. By studying supplier development practices in Ericsson empirically, this thesis intended to deepen knowledge of supplier development practices in the telecommunications industry. Method: This thesis is a qualitative research study which utilizes the single-case study methodwith multiple interviews. The empirical findings were supported by both primary and secondary data. The interviews were conducted with semi-structured ways under the framework of the interview’s ethical considerations and interview guide. Conclusion: There are different strategies which include both direct and indirect strategies in different supplier development life-cycle stages in Ericsson. Sustainability is taken into consideration in designing, recruiting, implementing, evaluating and rewarding stages of supplier development life cycle. The findings have contributed to deepen the knowledge of supplier development practices empirically in the telecommunications industry.