The ethics, and ethical governance, of online research have been much debated, and a number of professional organizations have promulgated guidelines for researchers considering conducting their research online. This chapter offers an overview of the current position, suggesting relevant considerations in respect of different kinds of project, and highlighting some of the challenges and dilemmas that online researchers face. The chapter is oriented to three principal approaches to gathering Internet-based data: use of online methods to gather data directly from individuals, analyzing online interaction within virtual environments, and large-scale analysis of online domains. Amongst issues covered are those relating to data protection and regulation, data intrusion, and issues raised by norms of privacy and to what extent information on the Internet can be regarded as intentionally ‘public’. The discussion is grounded in the ethical regulatory framework developed in offline research, noting commonalities and differences.