The Arctic Oscillation (AO) is the dominant mode of the atmospheric circulation in the extratropical Northern Hemisphere, which exerts widespread influences on the Northern Hemispheric and regional temperature changes. AO can be generated via wave-mean flow interactions without the presence of the atmospheric external forcing. Hence, it is an essential component of the internal climate variability of the climate system. Investigating the interdecadal variation of the AO and its climate impacts helps to deepen the physical understanding of the observed climate change and variability in the Northern Hemisphere. Meanwhile, it also provides a scientific basis for the near-term projection of climate change and its uncertainty. This paper briefly reviews the studies on the temporal and spatial variations of the wintertime AO on the interdecadal time scales and its impact on the Northern Hemisphere climate. Three aspects are reviewed, including the physical mechanism of the influences of the AO on the interdecadal variations of the East Asian winter monsoon, the contribution of the AO to the long-term trend of the wintertime air temperature in the Northern Hemisphere, and the uncertainty of the AO’s influence. The possible issues that deserve future research are also discussed.