This research aims to focus the attention on the concept of "legitimation lie" in order to break the silence surrounding it and to shed light on an organizational phenomenon that is not as rare as what we could believe. Specifically, it provides an explanation of how some entrepreneurs succeed in acquiring initial legitimacy for their small and new businesses through lies. The study of the antithetical association of legitimacy and lies led us to focus on two research axes: on the one hand, the ethical considerations attributed to legitimacy lies and on the other hand, the process of their realization.On the theoretical level, our study required a reassessment of classical moral approaches, with the aim to offer a new alternative that goes beyond the operational limits encountered. In addition, the multi-dimensionality of lying process has been illustrated by the intersection of several disciplinary fields examining cognition, social exchanges and emotions.On the methodological level, this work was based on in-depth interviews conducted with 20 entrepreneurs of newly founded small businesses. The examination of the collected data was mainly based on thematic content analyzes preceded or completed, when necessary, by content analyzes or by practices appropriate to visual maps.The results suggest a process of legitimation through lies made of five phases: (1) a phase of identification of problems related to the organizational legitimacy in which the solutions usually practiced used are inaccessible. (2) A phase of construction of the lying’s tactic in which the entrepreneur identifies his / her collaborates, the victims and determines the form and content of the lie. During this phase, negative moral emotions, such as anxiety and guilt, are likely to emerge. These emotions reflect by their natures the ethical value associated to the lie. (3) A decision-making phase in which the entrepreneur, pushed by his ambitions and other environmental factors, rationalizes his behavior and neutralizes the negative emotions felt. (4) A phase of realization of the lying’s tactic and (5) a phase of control.The examination of the ethical considerations of lies revealed a "free individual moral space" - representing a margin between social and professional ethical standards, individual ethical norms and the circumstances surrounding the lies, where entrepreneurs allow themselves the right to use some forms of lie, according to their own rationality operating in that margin, without perceiving themselves as overstepping ethical limits.