This paper provides an elaborate general equilibrium framework by including informal economic activities in a model of trade, migration and unemployment. Existence of informal activities is critical in generating positive employment effects of liberal trade policies. Following a tariff cut informal wage increases and rate of unemployment goes down under reasonable conditions. Next we generalize the benchmark model to capture the phenomenon of sequential migration: from agriculture to urban informal sector, and then to urban formal sector. Positive employment effect of reformatory trade policy partly owes to the fact that the presence of informal sector directly reduces the cost of migration and, hence, further induces the process of outmigration from agricultural sector. The paper also extends the benchmark model to include both informal intermediate and final good.