Fostering well-being at the workplace is no longer a concern limited to large employers obliged to comply with European Sustainability Reporting Standards. It has also become a vital issue for small and medium-sized enterprises (SMEs). There is a need for a deeper understanding of how SMEs develop and utilize well-being practices, and whether such efforts contribute to their long-term sustainability. Undoubtedly, practices aimed to ensure employee well-being (EWB), including those of sustainable human resource management (SHRM), cannot be simply transferred from large companies to SMEs, due to the unique attributes of the latter and different contextual factors affecting their activities. Despite the recognition of this specificity, the sustainability-oriented stream of HRM research in SMEs remains limited, including the individual-level outcomes of SHRM beyond work performance, such as EWB. Through a systematic literature review, this study addresses the above gap, as it aims to define the state of research on employee well-being in SMEs in the context of sustainability in HRM and workplace practices.