The NIMBY (Not In My Back Yard) concept is commonly using to explain public opposition to new developments near houses and communities, such as: wind farms, electricity pylons, large dams, medium and maximum security prisons, commercial nuclear power plants, and gambling casinos. Despite its common use, the concept has been extensively critiqued by social scientists as a useful concept for research and practice. In this article we attempt to explain the NIMBY syndrome referring to psychological factors. Four hypotheses of this phenomenon were included: the spatial theory, understanding of the NIMBY phenomenon as selfish, NIMBY syndrome recognized from a perspective of the dynamics of attitudes, and finaly NIMBY syndrome as the sense of territorial identity. The NIMBY syndrome theory has also been analyzed from the point of view of impacts in social factors.