This paper aims to identify the relevant factors to consider in the decommissioning process of offshore oil and gas platforms. In five databases, using a systematic literature review of articles published from 1999 to 2020, 88 papers were analyzed. The factors were then grouped into two dimensions: (i) effect and (ii) technique in which we identified 161 factors for the decommissioning planning of offshore oil and gas platforms. The category with the highest relative importance in the decommissioning effect dimension was environmental (51%), and in the technical dimension it was the project management category (49%). The relevant factors depend on the specifics of each platform, such as the type of platform and the region where it is located. The results contribute to the evaluation of decommissioning studies over time and highlights areas of offshore platform decommissioning that need further research. The global list of factors can be used as a basis for the planning of offshore oil and gas platform decommissioning and in other offshore industries.