The contribution of state renewable energy portfolio standards (RPS) to green business and job growth is controversial. This research estimated the contribution of RPS to state green industrial growth empirically by stipulating and econometrically controlling for a range of state economic growth variables and, having done so, adding RPS variables. Our modeling framework assumed that if RPS have any effect on the green economy in a state, the effect occurs after a period of social and economic adjustment processes that began when the RPS were enacted. Our findings indicate that the presence of RPS have no discernible effect one way or the other on green job growth, but the persistence of RPS through time does cause an increase in the number of green businesses.