Synovial monocytes from untreated oligoarticular juvenile idiopathic arthritis patients were investigated to understand their role in chronic inflammation. These monocytes displayed increased T‑cell activation, resistance to cytokine production after stimulation and enhanced efferocytosis. Broad‑spectrum phosphorylation assays and co‑culture experiments with synovial fibroblasts identified IL‑6/JAK/STAT signalling and cell–cell contact as key drivers of the pro‑inflammatory phenotype. Targeting the IL‑6/JAK/STAT axis may help restore synovial homeostasis in childhood‑onset arthritis.