Transient overvoltage is a dominating cause in damaging device insulation, which possibly leads to severe failures of power system and threatens safety operation of the power system. Thus, it is increasingly emphasized to equip the system with accurate measurement ability for the transient overvoltage. This paper reviews the existing technologies on measuring transient overvoltage, which are categorized by contacted and non-contacted technologies based on working principles of the corresponding sensor. In details, the principles, advantages and disadvantages, and application ranges of various transient overvoltage measurement techniques are summarized in terms of voltage divider, bushing tap, GIS sensor, field sensor, optical sensor, etc.