Mesenchymal stem cell-based therapy has great therapeutic potential for temporomandibular joint?(TMJ) cartilage repair. However, the behavior of mesenchymal stem cells in the inflammatory milieu following their delivery remains poorly understood. Synovial fluid-derived mesenchymal stem cells?(SFMSCs) are a promising resource for TMJ cartilage repair, as they are easily obtained from patients with TMJ disorders?(TMD). In this study, we obtained SFMSCs from patients with TMD and expanded them in?vitro; we then stimulated the cells with interleukin?(IL)?8, IL-1β, IL-6, IL-10, tumor necrosis factor?(TNF)-α and IL-12p. The cells expressed CD90, CD44, CD105 and CD73, and were negative for CD45, CD34, CD11b, CD19 and HLA-DR. They could be induced to differentiate into osteogenic, chondrogenic, adipogenic and neurogenic lineages in?vitro. Only the levels of IL-6 and IL-8 were upregulated significantly following stimulation with IL-8, IL-1β, IL-6, IL-10, TNF-α and IL-12p. Furthermore, IL-6 and IL-8 expression was driven mainly by IL-1β-dependent nuclear factor-κB?(NF-κB) pathway activation, and was independent of IL-8, IL-6, IL-10, TNF-α and IL-12p. IL-6 and IL-8 expression was inhibited completely by treatment with the NF-κB inhibitor, BAY11-7082. SRY-box?9?(SOX9) was downregulated and matrix metalloproteinase?(MMP)13 was upregulated upon chondrogenic differentiation induced in the cells also exposed to IL-1β. Sulfated glycosaminoglycan production was also reduced upon chondrogenic differentiation in the presence of IL-6, but not IL-8. Thus, IL-1β in the inflammatory milieu is crucial in regulating SFMSCs. In doing so, IL-1β impedes the chondrogenic differentiation of SFMSCs. The upregulation of IL-6 and NF-κB pathway activation also contribute to this biological behavior. The findings of our study indicate the potential adverse effects of IL-1β on the chondrogenic differentiation of SFMSCs, and may thus provide new insight into the pathogenesis of TMD.