In 2017, two major water-focused Multi-Donor Trust Funds, the Water and Sanitation Program (WSP) and the Water Partnership Program (WPP), were integrated in creating the Global Water Security and Sanitation Partnership (GWSP), towards realizing its “Water-Writ Large Agenda”. The GWSP has been embedded in the Water Global Practice of the World Bank, allowing it to play a key role in supporting countries to deliver water sector results and achieve SDG 6. Learning-oriented and formative, the evaluation takes stock of progress made since the merger, specifically on addressing recommendations from the evaluations of the WSP and WPP, which themselves informed the creation of the GWSP. It also assesses if, and the extent to which, the GWSP is on track to significantly advance the three pillars of the Water GP’s Strategic Action Plan. The assignment focused on four areas: i) the external environment; ii) organizational coherence; and iii) performance and delivering sustainable results; and iv) organizational capacity management and governance. Data collection methods included an in-depth document review, database analysis, key informant interviews and country case studies.