Sustainable supply chains are a crucial strategy adopted by companies to improve their environmental, social, and economic results in response to market demands. Digital transformation introduces a new paradigm in the industry, reconfiguring manufacturing, products, services, and supply chains themselves. While sustainable supply chains and digital transformation in supply chains (known as Smart Supply Chain) are gaining prominence in both literature and practice, it is still unclear how digital transformation can effectively support sustainable supply chains. While the Smart Supply Chain approach aims to improve productivity, quality, and flexibility, sustainable supply chains seek to establish trust and transparency in their sustainable processes by integrating environmental responsibility in a competitive way. The purpose of this thesis is to explore how digital transformation can effectively strengthen sustainable supply chains. This study aims to provide insight into the relationship between digital transformation and sustainable supply chains. To achieve this objective, the thesis combines quantitative and qualitative methods.   The research involved a survey of 473 manufacturing companies to elucidate how Smart Supply Chain can contribute to sustainability in supply chains, in terms of both environmental and financial results. To complement this focus, a qualitative research study was conducted through a multiple case study approach, which focused on leading companies in the manufacturing sector that have implemented sustainable practices. The aim of this qualitative study was to understand how these companies effectively incorporate sustainable practices, supported by the application of the Smart Supply Chain concept. The thesis results indicate that the Smart Supply Chain approach effectively promotes the development of sustainable supply chains, enabling the intelligent and sustainable creation of long-term value. This approach is noteworthy for using Smart Supply Chain as a foundation for the development of environmental, social, and economic responsibility at all stages of supply chains. Therefore, this study's primary contribution is aligning with the United Nations' sustainable development agenda. It promotes the adoption of sustainable practices in supply chains to reduce carbon footprints and create carbon-neutral networks. Additionally, it aims to develop partnerships between different actors in the chain to reduce inequalities and promote economic growth.