Small and medium-sized enterprises (SMEs) cannot be considered a "shrunken" of large enterprises. They are highly heterogeneous, usually have more informal organizational characteristics, and do not have departments dedicated explicitly to corporate social responsibility (CSR) tasks. Therefore, research on CSR in SMEs faces many challenges. The situation is a complex phenomenon, primarily because the nature of CSR is influenced by the environment uniqueness in which it is studied or practiced. This paper aims to identify the main themes of qualitative research on CSR in SMEs. The Web of Science database was chosen to identify relevant literature, and the research focuses only on peer-reviewed articles published in English up to November 2022. The resulting dataset was created by selecting articles with a qualitative or combined approach. A total of 21 articles published in 10 journals were identified. The published studies contained the following research streams: 1. SMEs' CSR activities and reasons for involvement, 2. Ethical values of the entrepreneur or owner-manager and their impact on SMEs' social responsibility, 3. Relationships with stakeholders, 4. The nature of SMEs' social responsibility implementation. The findings of this study contribute to the CSR literature and have important practical implications for SME managers. The conclusion also formulates questions to stimulate the potential for further research.