This paper tries to highlight the territorial development in the governorates of South East Tunisia on the border with Libya. Our main objective is to show the existence of a direct relationship between regional diparity and work in informal trade.This work proposes to aggregate a set of regional development indicators of each delegation in order to draw up a typology of the delegations as well as to calculate a territorial development index for each delegation and to discern any failures hindering their development. Also, this analysis addresses the subject of informal trade in southeastern of Tunisia. Following this, a survey will be made with the informal trade actors to analyze their situations and finally an analysis of the state intervention as well as recommendations will be proposed. Our work has shown that regional and local disparity is one of the causes of informal trade in the southeast. As well as the workshops, that we organized confirmed that most of the players in the informal trade are unemployed young people. Here, there are also people who are currently working and who a fixed income, but they are informal traders.