This chapter analyzes appointment mechanisms in local participation channels in Mexico, examining their relationship with levels of social disadvantage. To do so, it draws on data from the National Census of Municipal Government and Territorial Demarcations of Mexico City and the Social Disadvantage Index. Using these sources, I explore how the procedures for accessing participatory channels (open, by election, by selection, or by invitation) vary depending on the socioeconomic conditions of the municipalities. The results of nonparametric tests reveal that municipalities with lower levels of social disadvantage tend to adopt more selective appointment mechanisms. In contrast, those with higher levels of disadvantage tend to favor more open and consultative processes. These findings suggest that socioeconomic context affects both the composition and legitimacy of participatory bodies, at times constraining citizen influence in local decision-making. The study underscores the importance of understanding how these dynamics operate when designing strategies aimed at balancing representation and strengthening local governance.