A transmission line refers to an extended conductor that is specifically designed, often bundled together, to facilitate the transportation of a substantial quantity of electrical power at exceptionally high voltages from one station to another, accommodating the fluctuation in voltage levels. Insulation serves as a barrier between the conducting parts of a cable and the surrounding environment, preventing direct contact and minimizing the risk of electrical shocks to personnel. It helps maintain a safe operating environment for workers and the general public. In addition, Insulation helps maintain the desired voltage levels by preventing leakage or losses along the cable. It ensures that the power is efficiently transmitted without significant voltage drop, which is crucial for the proper functioning of electrical equipment and appliances connected to the power system. The necessity of insulation brings the paramount significance of insulation testing in transmission lines. This paper briefly presents the insulation testing techniques in transmission lines and summarizes the advantages and disadvantages of each method. Manuscript profile