Mesenchymal stromal/stem cell (MSC) therapies are increasingly explored as novel regenerative and immunomodulatory approaches to treat or prevent diseases (Pittenger et al., 2019; Hmadcha et al., 2020; Moll et al., 2020b; Ringdén et al., 2022). These cells exhibit potent paracrine properties that can modulate host immune responses, lower inflammation, and orchestrate endogenous tissue repair, at both the local and the systemic level through multiple pathways (Singer and Caplan, 2011; Doorn et al., 2012). MSCs possess tropism toward damaged and inflamed tissues, where they can engraft short-term and exert their therapeutic effects by both direct and indirect mechanisms (Doorn et al., 2012; Galipeau and Sensebe, 2018; Soria et al., 2019). MSC products can be prepared from multiple sources (Moll et al., 2019, 2022), rapidly expanded and biobanked for clinical application. All these advantages make this cell type a versatile tool in regenerative medicine. The goal of our Research Topic is to highlight the latest advances in applications of MSCs for the treatment of a variety of diseases and their modes of action (MoA). A better understanding of the mechanisms underlying the therapeutic effect of MSCs can provide crucial insight into innovative strategies to enhance their effectiveness in clinical application (Singer and Caplan, 2011; Doorn et al., 2012; Galipeau and Sensebe, 2018; Moll et al., 2019, 2020b, 2022; Pittenger et al., 2019; Ringdén et al., 2022). The subjects covered within this Research Topic include: (a) Therapeutic application of MSCs for major clinical indications, (b) Cellular and molecular mechanisms underlying therapeutic effects of MSCs, and (c) Strategies for enhancement of the therapeutic effects of MSCs and their products. Here, we summarize the 37 manuscripts that were submitted to this Research Topic (Figure 1).