As South-South trade gains new weight in global exchange patterns, will environmental protection be enhanced or endangered? Environmental economists are generally optimistic that trade will lead to greater environmental protection, but see less chance of that in South-South trade; political economists make opposite arguments on both points. This article shows that South-South trade is dominated by a small set of fourteen countries, with most Southern countries continuing to be natural resource providers. Case studies of Brazil’s trade with China and with its South American neighbors reveal a policy framework that supports both of the opposed arguments: Southern countries can and do consider the environmental impacts of their production and trade, but strong counter-forces limit that effect.