<p>This article examines how ethical consumption is constrained by the configuration of social practices by focusing specifically on online fashion shopping. Existing ethical consumption research shows that consumers’ pro-environmental and pro-social concerns fail to translate into ethical purchasing actions. Such research has focused on the idea of a rational consumer motivated to act ethically. Conversely, we advance a socio-cultural perspective on ethical consumption by theorising ethics as a cultural-level general understanding that threads through consumption activities within social practices. Like other general understandings, ethics can become inculcated into specific practices, or obstructed from doing so, due to the configuration of a practice. Drawing upon qualitative research with 58 participants, our findings show how the configuration of online fashion retail consistently blocks ethical online fashion shopping. This fosters practice destabilisation, frustration and deepened ethical reflexivity, triggering strategies for practice reconfiguration. While some practitioners stop shopping online, for others, the struggle to shop ethically becomes habituated within online fashion shopping. We contribute to the literature on ethical consumption by establishing how ethics fails to embed in consumption and by providing a socio-cultural theorisation of ethics as a general understanding that can be enabled or constrained in social practices. The significance of these contributions lies in their ability to determine that ethical consumption is constrained beyond the level of individual agency; that it can be incredibly frustrating for consumers to attempt to find individuated solutions to systemic problems; and that ethical consumption is not just the responsibility of ethically minded consumers.</p>