Long non?coding RNA (lncRNAs) have been identified to play important roles in multiple human diseases via the regulation of cell proliferation, cell invasion, or cell death. However, little is known about the role of lncRNAs in the process of shifts in the Th17/Treg ratio during the progression of juvenile idiopathic arthritis (JIA). The aim of the present study was to determine the role of lncRNA RP11?340F14.6 in the shifting of the Th17/Treg ratio in JIA. The distribution of the T cell subgroup was detected by flow cytometry in peripheral blood mononuclear cells from patients with JIA and healthy controls. It was found that the expression of lncRNA RP11?340F14.6 was upregulated, and to positively correlate with that of retinoic acid?related orphan receptor gamma?t (RORγt), and to negatively correlate with Foxp3 expression in patients with JIA. RP11?340F14.6 induced the expression of its neighbor, P2X7R. Through a P2X7R?independent approach, this lncRNA was also found to play a pivotal role in stimulating Th17 differentiation and simultaneously suppressing Treg distribution. Taken together, the findings of the present study demonstrate that RP11?340F14.6 specifically binds to P2X7R, which results in the continuous activation of P2X7R. Thus, RP11?340F14.6 may serve as a promising therapeutic target for the treatment of JIA.