This study investigates the interannual variability of zonal mean temperature in the wintertime Northern Hemisphere stratosphere and mesosphere measured by Aura-MLS (Microwave Limb Sounder). Results show that the wintertime Arctic temperature is modulated by the phase of the equatorial quasi-biennial oscillation (QBO) wind. On the whole, the 40-hPa QBO easterly phase corresponds to a warmer (colder) northern polar stratosphere (mesosphere) and vice versa. Accordingly, composite differences show that the planetary waves in the winter Arctic stratosphere and lower mesosphere are stronger when the equatorial 40-hPa QBO in its easterly phase. The presented findings are consistent with the established relationship between the QBO phase and the northern winter polar vortex.