Despite increased awareness and consumer interest in green products and a pre-disposition to purchase more environmentally friendly products and services, we can often notice the lack of correspondence between consumers speech and their actions. Therefore, there is an inconsistency between attitudes and behavior, also called gap. It can be said that there is often an environmentally friendly pre-disposition (attitude) which does not often turn into action (behavior). Thus, although several studies have been conducted on consumer behavior, not a definitive explanation of the gap phenomenon and not a precise behavioral model for its compreehension was found so far. The present study aims to contribute to the literature for a deeper understanding of this phenomenon in a new light by analyzing the influential factors on the gap from the perspective of different generations. The study seeks to understand the main influential factors that contribute to increase or reduce this gap between attitude and environmentally conscious behavior that occur in members of Baby Boomers (BB) generation and Y generation, as well as their similarities and differences. For the development of the thesis thirty in-depth interviews were conducted with consumers residing in Rio de Janeiro; fifteen belonged to the Baby Boomers generation and fifteen to the Y generation. The analysis of the results used the Atlas ti software in order to facilitate interpretation and data organization. The results show the main influential factors on the gap on both generations (BB and Y), by analyzing five consumption activities: environmentally friendly products, energy, water, transportation and recycling / disposal. The results show the main similarities and differences between the behavior of the BB and the Y generations indicate greater concern and more conscious behavior by individuals of generation Y in terms of some consumption activities. At the end, a model of ecologically conscious behavior is proposed to better understand the phenomenon called gap. The main factors that contribute to increase or reduce this gap in both generations are highlighted.