The NGO Forum on Cambodia has been working on the issue of hydropower since the late 1990s. Various NGOs formed the Sesan Working Group in 2003 (only dams along Sesan River), then the 3S Working Group in 2005 (dams on Sesan, Sekong, and Srepok Rivers). Through the addition of new CSOs and an expansion of geographical scope to the whole of Cambodia, the coalition changed its name to the RiversCoalition in Cambodia (RCC) in early 2007. NGO Forum#s Rivers Coalition in Cambodia Project has undertaken a vital role to facilitate RCC members and other stakeholders including youth group, academics, lawyers and other interest groups to work with and for dam #affected communities, both men and women, to address issues arising from an increase in the number of dams on the Mekong mainstreaming and its tributaries. We aim to intervene to enforce / influence the progress of dialogue and discussion on regional solutions for good water governance in the Mekong river basin. In this regard, the RCC has been addressing the issues through working with its network members and other partners to implement activities of the Rivers Coalition in Cambodia Project. The unrestricted fund of Oxfam Novib, through Water Governance project, funds NGO Forum-RCC 2019-2020 to enhance the functioning of RCC that align with its action plan 2018 to 2020, which is part of NGO Forum new strategic plan 2018-2023 that was developed with participation of RCC members and affected community. This project supports RCC to function its roles on key activities on promoting policy dialogue and influencingon hydropower dam development to hold the government and developers accountable, awareness raising and capacity building for its members, supporting research, producing influencing materials on hydropower projects and its impacts. This aligns with objective number 2 of Oxfam Mekong Regional Water Governance Program and Inclusion Project to hold infrastructure developers to account and promoting standard, and consistent with Oxfam in Cambodia Natural Resources Governance Program objective number 2 to improve and enforce government relevant law and policies in accordance to international principles and standards related to natural resources governance. This project enables RCC and its members to actively engage with sub-national, national and regional partners to influence Cambodia and transboundary policy improvement on water governance in the Mekong Cambodia and the region and ensure meaningful engagement and participation of community in the policydevelopment consultation process. The RCC is also contributing to awareness raising and advocacy on gender issues in response to Cambodia#s energy planning and hydropower development into its project planning and implementation. For instance, a Lower Sesan 2 dam resolution committee has been formed by engaging both sub-national and national government, NGOs, affected communities, and private companies to address dam affected issues to local people, especially women and vulnerable people. In addition, TheRoyal Government of Cambodia (RGC) has recently announced the proposed Sambour hydropower development on the Mekong mainstream (RGC, 2016). It will be the largest hydropower dam in Cambodia and the Mekong Lower Basin. If the dam is constructed, it wouldhave a negative impact on society, fish migration and vital ecological linkage between the Mekong upstream, the Tonle Sap Lake in Cambodia and the Mekong Delta in Vietnam. The evidence from the feasibility study report of Sambor Hydropower Station indicatedthat the proposed Sambor dam will directly impact 19,034 people. They will need to be resettled to other places because their current habitats and natural resources will be permanently flooded in the dam reservoir (Liu, 2008). A scientific study predictedthat fish yields will reduce by 16% - 30% or 98,000 # 182,000 tons and there will be reductions in other aquatic animals if the proposed Sambor dam is developed, (IFReDI, 2012). Water flow from the Mekong River will change which will have an extreme impact on the water level in Tonle Sap Lake. It is also predicted that the water level will increase by 1.2 m in the dry season and decrease by 1.0 m inthe rainy season (Sushu et al, 2010). This proposed dam which has been known negatively impactful on fishery sector, local livelihoods and biodiversity in the Mekong, is a key advocacy issue for NGO Forum-RCC to take lead and coordinate with other stakeholders for policy influencing. The recent MRC#s council study shows that the hydropower plans would reduceamount of sediment reaching the Mekong Delta by 97%. The sediment improves and replenishes the entire basin and supports agriculture, fishery and water quality that would support local economy of riverine community. Dam reservoir and infrastructure willnegatively impact fisheries resources by obstructing access to important spawning grounds . These would cause fish stocks to decline dramatically by 2040 and eliminate migratory fish in large part of the Mekong (MRC, 2017). Individual country likes Cambodia will reduce fish biomass by 35%. This requires the important role of RCC to coordinate and influence water governance related policies to ensure sustainability and full participation of affected communities. In this regard, affected communities are empowered and play the role as active change agents of decision-making process on hydropower policy and regulation. Through this project RCC aimed to achieve the key outcome #By 2023 RCC has effectively influenced hydropower policy processes to ensure sustainability and full participation of affected communities.# The specific outcome of the project is that, #By the end of 2019, a content of renewable energy and water resource management are incorporated intogovernment#s plan and policy and on the otherhand,an issue of LS2 dam affected community is addressed by the national and provincial authorities.#