Expert group meeting on Monitoring, Assessment and Data Exchange of the United Nations Economic Commission 1992 Convention on the Protection and Use of Transboundary Watercourses and International Lakes (Water Convention) Joint monitoring and assessment of transboundary waters and information exchange are among the key obligations under the Convention. Initiating information exchange is fundamental for developing cooperation. Comparable information across a transboundary basin or aquifer is necessary to form a common basis for management and related decision-making. In practice, this requires harmonized and comparable methods for monitoring and assessment. As result of the outcome of the survey for the next Programme of Work 2022-2024 of the Water Convention and the outcome of the discussion at the Fifteenth meeting of the Working Group on Monitoring and Assessment and Global workshop on Data Exchange and information (4-6 December 2019), this expert group meeting on Monitoring and Assessment will discuss in detail the proposed activities on monitoring, assessment and data for 2022-24, notably the update of guidelines on Monitoring and Assessment and will serve to review and discuss different options, hear about relevant experiences to consider, orient the work and agree about the next steps.