Micro and small enterprises (MSEs) are essential for economic and social development globally, as they represent a significant proportion of employment and production. Nonetheless, these enterprises confront substantial difficulties in incorporating sustainable practices, largely attributable to their limited financial resources and capacity, difficulties in accessing relevant information, scarcity of operational resources, and the lack of regulatory frameworks to facilitate their operations. The adoption of sustainable practices is presented as a viable strategy to improve both their competitiveness and profitability, while contributing to social and environmental well-being. For this reason, a systematic review was conducted to answer the question: What are the sustainability practices of micro and small enterprises? The objective was to compile the business sustainability practices that have been documented in MSEs. Bibliographic research was carried out in different databases of articles published between 2012 and 2023. The main results were presented through a qualitative systematic review. The studies carried out in MSEs from different sectors reported practices related to technological innovation, product innovation, strategic management, as well as economic, social and environmental aspects. Longitudinal studies are required to assess the long-term impact of sustainable practices on MSEs.