Literature argues that there is a relationship between citizen knowledge concerning laws and legal instruments and the level of public participation related to environmental and spatial planning policies, referring that the normative ignorance prevents citizens to fully exercise their rights. In this paper, the authors characterize the knowledge of the citizen´s about the laws and the legal instruments of public participation in the Portuguese democracy. Regarding the mechanisms of citizen participation on environment and spatial planning policies, the authors observed that half of the participants know that the law account for citizen participation (50.4%), while 56% knows what the laws provides. Moreover, almost 87% have heard about the legal instruments for planning and territorial management and about 53% knows what they are. Among the individuals that reported not knowing that the laws predict their possibility to participate, ¾ do not get involved in participative actions. Most of the participants stated that they were aware of the existence of public participatory components (laws and legal instruments) for spatial planning, and a significant relationship between the knowledge and citizen´s participation concerning to local policies was achieved (P = 0.023).