Abstract: Short-range ordering (SRO) is one of the most important structural features of high entropy alloys (HEAs). However, the chemical and structural analyses of SROs are very difficult due to their small size, complexed compositions, and varied locations. Transmission electron microscopy (TEM) as well as its aberration correction techniques are powerful for characterizing SROs in these compositionally complex alloys. In this short communication, we summarized recent progresses regarding characterization of SROs using TEM in the field of HEAs. By using advanced TEM techniques, not only the existence of SROs was confirmed, but also the effect of SROs on the deformation mechanism was clarified. Moreover, the perspective related to application of TEM techniques in HEAs are also discussed.