ABSTRACTAllergic rhinitis (AR) is one of the most frequently observed diseases in otorhinolaryngology, a global issue that alters the quality of life of patients. Both B cells and follicular helper T cells (Tfhs) have important roles in allergic diseases. However, how Tfhs and B cells interact to modulate allergic rhinitis pathogenesis remains unclear. In this study, two models of allergic rhinitis were examined, including the co‐culture of follicular helper T cells (Tfhs) isolated from mouse spleen with B cells. To further define the mechanism, exosomes from Tfh cells were isolated and added to B cells. Bulk RNA sequencing (RNA‐seq) analysis was used to compare exosomes derived from Tfhs cells in a mouse model of allergic rhinitis and exosomes derived from Tfhs cells in wild‐type mice. Among them, miR‐149‐5p was observed to be lowly expressed in the allergic rhinitis group, which was confirmed using qPCR. miR‐149‐5p mimics or inhibitors were utilised to overexpress or knock down miR‐149‐5p in Tfhs, which were then co‐cultured with B cells, demonstrating that miR‐149‐5p is negatively correlated with B cell proliferation and maturation. The function of WNT3A, a target gene of miR‐149‐5p, and the downstream effector AXIN2 on the proliferation and maturation of B cells were predicted and verified. We show that miR‐149‐5p packaged in Tfhs‐derived exosomes induces B cell proliferation and maturation through the WNT3A/AXIN2 axis. The discovery will contribute to new ideas for the treatment of allergic rhinitis.