While the world rushes to become more sustainable, there is a strong attitude-behaviour gap in the emerging markets when it comes to green products. There is a growing awareness of the environment but sustainable buying behaviours are still limited due to the widespread greenwashing, infrastructure and institutional distrust. This conceptual paper integrates the existing literature and presents a theoretical framework that connects the constructs of green product knowledge, consumer trust and sustainable buying behaviour in the context of emerging markets. The paper is based on an extended theoretical model that combines the Theory of Planned Behaviour, Signalling Theory and Institutional Theory as a basis for the cognitive antecedent of green product knowledge. But this knowledge does not just have an immediate effect on behaviour; it works best by promoting consumer confidence. Trust is the psychological conduit that validates corporate environmental claims in low-trust environments that are characteristic to many emerging economies, that helps reduce perceived purchase risks and that helps to resolve cognitive dissonance. This study helps to provide conceptual boundaries of these links and to differentiate subjective knowledge from objective knowledge, thereby improving the theory of sustainable marketing. Moreover, it provides strategic, non-quantitative suggestions to the policy makers, brand managers, and regulators that can help create real and trustworthy green consumption. The paper ends with a comprehensive agenda for future qualitative, longitudinal and mixed methods studies.