This contribution discusses the legal framework of online advertising and common legal issues pertaining thereto. This paper also addresses the implementation of general legal provisions to online advertising issues in different jurisdictions and the diversity of approaches. It provides the legal boundaries that are specifically applicable to online advertising. The paper then provides a legal analysis on online advertising with a focus on Turkish laws and practice. In the conclusion, there are general evaluations on the legal aspect of online advertising and certain suggestions on the development of a legal framework on online advertising.