Purpose – The purpose of this paper is twofold: to provide an overview of related studies and to highlight research gaps and questions that need to be addressed. Research conducted in three-dimensional online environments constitutes a different research context, not least because it involves the recruitment of avatars in the research process. Researchers need to appreciate better the ethical concerns that arise in this novel, fast-evolving context and how these concern different stakeholders. Design/methodology/approach – The paper employs an interdisciplinary desk-research (...) approach. It critically reviews related literature, highlights the involved stakeholders, discusses ethical issues from a marketing research perspective and concludes with a discussion of related studies and research gaps, providing direct future research avenues. Findings – The characteristics of the 3D online environments and the behaviour and experiences of their users set the boundaries and guide the way regarding the ethical research in this context. Research limitations/implications – The paper does not present primary empirical results, instead it reviews and critiques related literature in 3D online environments and sets the agenda for future research. Practical implications – The paper provides ethical guidelines and identifies blurred areas in conducting or participating in research in 3D online environments. Originality/value – Based on earlier studies and examples of ethical concerns when studying 3D online environments, this paper emphasises the parameters that should be taken into consideration in current and future research studies. (shrink)