Purpose: This master thesis aims to investigate the SMEs' perceptions about digitalization and sustainability of the firm and distinguish the factors that affect them. Furthermore, it illustrates how the SMEs’ digitalization process is linked to their sustainability.  Theoretical approach: This master thesis is based on the previous research and literature on SMEs’ digitalization and sustainability of the firm. Additionally, it proposed a conceptual model that links SMEs' digitalization process to their sustainability. Methodology: This research followed the qualitative method in which the data was obtained through semi-structured interviews with eight SMEs. These SMEs are located in Sweden, France, and Iran. However, the responses were analyzed based on the secondary analysis method. Findings: The study's findings demonstrate that digitalization affects an SME's sustainability through growth, competitiveness advantages, value creation, internal efficiency, and saving costs. Regardless of where SMEs are located, they mostly have the same perception of digitalization and insufficient knowledge about the firm's sustainability, and mainly the same factors affect their digitalization process and sustainability. Practical implications: The results of this study could provide a perspective on adopting the new technology by SMEs. It could inspire SMEs to increase their digitalization capability by adopting new technologies to ensure long-term sustainability in their organizations. It also sheds light on confusing the firm’s sustainability with SDGs, which SMEs must investigate. Originality/Value: This study adds to the digitalization and sustainability of the firm literature by investigating SMEs' perceptions about digitalization and firm’s sustainability, factors that influence the digitalization and sustainability process of the SMEs and examining how SMEs' digitalization processes are linked to their sustainability