This work presents findings on whether trade liberalization is a curse or blessing for developing countries with evidence from China and Zambia. It is premised on three specific objectives; firstly, to find out how openness to trade influences economic performance as measured by GDP; secondly, the subsequent overall welfare of people in the economy and thirdly, the constraints behind gains from trade in a liberalized regime. In order to yield composed results, the work uses both descriptive and empirical approaches. It also finds that high natural resource contribution to GDP and high exports in primary commodities are the major constraints to the gains from trade.