This paper reviews eleven widely used sustainability indices: the Living Planet Index (LPI), Ecological Footprint (EF), City Development Index (CDI), Human Development Index (HDI), Environmental Sustainability Index (ESI), Environmental Performance Index (EPI), Environmental Vulnerability Index (EVI), Index of Sustainable Economic Welfare/Genuine Progress Index (ISEW/GPI), Well-Being Index (WI), Genuine Savings Index (GS), and Environmental Adjusted Domestic Product (EDP). The authors find that these indices fail to meet fundamental scientific requirements in terms of normalization, weighting, and aggregation. Normalization and weighting are often arbitrary and lack transparency, while aggregation methods are not consistently applied. Scientific rules exist to ensure consistency and meaningfulness in composite indices, but they are frequently ignored. As a result, the sustainability indices currently used in policy practice are likely to be either useless or misleading for concrete policy advice. The paper highlights the need for more rigorous scientific methods in the construction of sustainability indices to ensure they are meaningful and consistent.This paper reviews eleven widely used sustainability indices: the Living Planet Index (LPI), Ecological Footprint (EF), City Development Index (CDI), Human Development Index (HDI), Environmental Sustainability Index (ESI), Environmental Performance Index (EPI), Environmental Vulnerability Index (EVI), Index of Sustainable Economic Welfare/Genuine Progress Index (ISEW/GPI), Well-Being Index (WI), Genuine Savings Index (GS), and Environmental Adjusted Domestic Product (EDP). The authors find that these indices fail to meet fundamental scientific requirements in terms of normalization, weighting, and aggregation. Normalization and weighting are often arbitrary and lack transparency, while aggregation methods are not consistently applied. Scientific rules exist to ensure consistency and meaningfulness in composite indices, but they are frequently ignored. As a result, the sustainability indices currently used in policy practice are likely to be either useless or misleading for concrete policy advice. The paper highlights the need for more rigorous scientific methods in the construction of sustainability indices to ensure they are meaningful and consistent.