The 2023 Murray—Darling Basin (MDB) Outlook will report on the current condition and trend, as well as predicted future trajectories of several water related values under a range of climate scenarios. These values will cover the environmental, social, economic and cultural values of the Basin. The MDB Outlook will examine at predominantly a whole-of-Basin scale, the main drivers of water related values across environmental, community, economic and cultural values. The Environmental Values (EV) chapter of the 2023 MDB Outlook will provide an assessment of seven environmental attributes, under four EVs: water quality; water-dependent ecosystems; ecological processes and animal populations. This report contributes to the first phase in the development of the EV chapter for the 2023 MDB Outlook, by undertaking a structured literature review of each of the EVs. This review has been compiled by a group of MDB subject-matter experts from three institutions and targets the published and readily available technical literature to assess the current state of understanding and identify key gaps in knowledge and data. This technical report concisely reviews each identified EV with specific focus on the current indicators, data, risks and threats, trends and knowledge gaps. Broadly, many of the EVs attributes explored in this review show evidence of continuing decline, or at best, their current condition is stable. For many EVs, altered flow regimes and inadequate hydrological connectivity were identified as the major driver of these declines. The literature review forms the first stage of the development of the EV chapter and explores possible directions for phase 2 of the MDB Outlook project, which includes assessing and grading indicators for each EV attribute to understand the current condition, trend and predicted future of the EVs of the MDB.