Background. The study's relevance lies in analyzing the gender wage gap in Ukraine's energy sector, using survey data from energy companies to identify its key drivers. The study aims to provide empirical insights into the causes of this gap. The object of the study is the processes of wage determination and pay inequality across professional groups within energy companies, while the subject is the approaches and tools for assessing gender-based differences in wages and career progression. Applying the factor-weighted gender pay gap method, the research estimates disparities between women and men with comparable education, tenure, and hierarchical positions. The findings show that unequal access to wage-enhancing qualifications and experience is the main driver of the gap, with evidence of informal institutional barriers limiting women's career progression. These results have practical implications for revising gender equality policies and strengthening women's roles in the energy industry. Methods. The article applies the factor-weighted gender pay gap method, grouping employees by education, tenure, and position in the qualification hierarchy to estimate gender pay differences. Results. The study showed that the gender wage gap in Ukraine's energy sector is mainly driven by unequal access of women to wage-enhancing qualifications and experience, with evidence of informal institutional barriers that hinder their career progression. Conclusions. The study concludes that gender wage inequality in Ukraine's energy sector mirrors patterns seen in Europe, is most pronounced at lower qualification levels, and is reinforced by "men's clubs" practices, highlighting the urgent need to remove institutional barriers to women's career advancement, especially under wartime labor shortages.