Gas Chromatography (GC) serves as a pivotal technique for detection and diagnosis of faults in oil immersed power transformers (OIPTs). This method relies on the identification and analysis of the gases dissolved in insulating oil, which are produced because of degradation of insulating materials under thermal and/or electrical stresses. Key fault indicators such as hydrogen, methane, ethylene, ethane, and acetylene are separated and accurately quantified using GC equipment. The qualitative and quantitative analysis of these gases facilitates precise identification of various fault types and severities, including partial discharge, overheating, and electrical arcing. Due to its high sensitivity, accuracy, and capability for early fault detection, GC is widely employed in preventive maintenance programs within the electricity industry to enhance the OIPTs reliability and prolong their operational lifespan. This paper offers a comprehensive review of established methods for the gas chromatography and, through an examination of prior research, aims to propose standardized approaches and diagnostic criteria for accurate fault detection in the OIPTs.