Commitment is a pillar of the consumer-brand relationship. It is often presented as the will of a customer to continue the relationship with its brand. Although this relational current is very studied by researchers, there remains still little developed. Thus, the literature did not examine the combination of commitment-boycott. This thesis aims on the one hand to the development of the theoretical framework for the quality of the relationship with the brand and also to improve understanding of the role of the perceived egregiousness between quality of the relationship and the boycott decision. The final survey shows that an effect of assimilation occurs and the consumer will have the intention to continue the relation when the gravity committed by the brand is of an economic nature. However, a contrast effect is released when the perceived gravity is qualified ethical where the commitment of the consumer will maximize this serious act and consequently, he will be ready to participate in a boycott action.