Steel structure plays a significant role in civil engineering. However, there are many factors affecting steel erectors and contractors to have a successful erection of steel structures. Thus, this study seeks to examine the factors affecting steel structure erection in construction projects within the context of a developing country. The study adopted a survey research method; a questionnaire to identify 47 factors, were assessed. A purposive sampling approach was used to identify 20 construction companies specialising in steel structures erections in Lagos, Nigeria. Sixty-three (63) questionnaires were distributed to the targeted population, which included 32 project managers, 14 project engineers and 17 site engineers of current and past steel structure projects carried out by the selected companies in Lagos. The data collected were analysed using descriptive and inferential statistics. The results revealed skills and experience, job site planning, availability of electrical power for tools, insufficient supervision and method of construction as the top most five factors affecting steel structure erection in construction project in Nigeria. The findings provide in-depth insight of the factors affecting steel structure erection in construction project that can help project managers in development of strategies for improving the erection of steel structure in the construction industry.