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This study investigates the Holton-Tan (HT) relationship based on re-analyses and co-ordinated experiments for present-day and warming scenarios within the SPARC Quasi-Biennial Oscillation initiative (QBOi) using Meteorological Research Institute Earth System Model version 2.0 (MRI-ESM2.0). The aim is to explore to what extent global warming modulates the HT mechanism in the effect of the QBO on the polar vortex. The simulations of the present-day conditions reproduce the zonal wind composite differences in the re-analysis; however, there are some discrepancies. In regions near the QBO (i.e. 20-40 degrees N), there is good agreement between the simulations and the re-analysis. Examples include the midlatitude (similar to 30 degrees N) lower (middle) stratosphere Eliassen-Palm (EP) flux convergence (divergence) anomalies between the easterly phase and the westerly phase of the QBO, which are common in the re-analysis and in the present-day and warming simulations. The influence of the QBO on the midlatitude lower stratosphere is associated with an effective waveguide for enhanced upward-propagating Rossby waves near the subtropical jet. At high latitudes, the significant (less significant) convergence anomalies of significant horizontal EP fluxes in the middle stratosphere are dominant in the re-analysis (the present-day simulations). In the warming scenarios, the QBO signatures of the zonal wind are strengthened with the significant EP flux convergence anomalies of less significant upward-propagating waves inside the polar vortex above 20 hPa. These results suggest that fundamental mechanisms behind the HT effect in regions near the QBO can be explained by enhanced upward-propagating waves associated with an effective waveguide (by inhibiting equatorward-refracting upward waves) in the lower-to-mid stratosphere. In the warming scenarios, however, HT mechanisms, especially inside the polar vortex, may have another pathway, different from that of the present-day climate.