This article explores the local political dynamics in forming Regional Regulations (Perda) on Gender Mainstreaming (PUG) following Presidential Instruction No. 9 of 2000. Focusing on Pandeglang Regency in Banten and Karawang Regency in West Java, the study examines factors influencing the success of PUG regulations, emphasizing women’s substantive representation in the legislature. Using a qualitative case study approach, it involves policy document analysis, in-depth interviews, and participatory observation in the two regencies. The findings highlight the crucial role of female legislators, executive officials, and political party support, particularly their commitment to gender issues, in successfully enacting PUG regulations. Despite challenges like bureaucratic inefficiencies, patriarchal cultural resistance, and limited budgets, legislators outside formal decision-making processes contribute significantly. Their support includes advocating for budgets and engaging civil society to oversee the process. This study offers key insights into local political dynamics and factors driving the success of PUG regulations in Indonesia.