Political theorists argue that justice for cultural groups must account for socioeconomic distribution, political representation and cultural recognition. Combining this tripartite justice framework with settler colonial theory, we analyse novel data sets relating to Aboriginal peoples’ water experiences in south-eastern Australia. We construe persistent injustices as ‘water colonialism’, showing that the development of Australia’s water resources has so far delivered little economic benefit to Aboriginal peoples, who remain marginalized from decision-making. We argue that justice theories need to encompass a fourth dimension – the vitally important socio-ecological realm – if they are to serve as conceptual resources for advancing Indigenous peoples’ rights and needs.