Purpose: This study aims to empirically analyze the determinants of OECD/DAC member countries’ aid in support of gender equality aid as a principle objective(gender marker 2). Originality: International community has emphasized gender equality as a key principle and norm of development cooperation, and OECD/DAC has led international discussions and policy efforts on aid for gender equality. While discussions on gender and development has focused on normative and practical aspects, the motivation of donors’ commitments for gender equality has remained unanswered. To bridge this gap, this study empirically analyzes the determinants of OECD/DAC member countries’ aid in support of gender equality and draws upon policy implications. Methodology: Considering that the aid amount is panel data left-censored at zero, the panel Tobit model is used for the analysis. Result: It is found that the aid in support of gender equality increases as a recipient country’s gender needs increase; women’s representation in a donor country increases; a recipient country tends to have received more gender aids from OECD/DAC members; and the presence of women’s international NGOs increases in a donor country. Contrary to our hypothesis, however, the gender aid decreases as donor government increases social spending on family benefits. Conclusion and Implication: A strong humanitarian motivation was found behind the donor countries' aid support for gender equality, and thus it is important to provide good information on recipient countries’ gender needs. Also, international community’s efforts to make the gender equality an international norm need to keep continued as they have been successful in increasing donors’ commitments for the gender equality. In particular, the role of women’s international NGOs has to be shed more light on. Also, donor countries’ social values affects their commitments towards the gender equality overseas. The tension between domestic social expenditure on family benefits and supports for gender equality overseas requires further research and discussion in the future.