This study examines empirically the relationship between Trade openness and Economic growth in Nigeria. The study covered the period 1990 – 2015, using ARDL approach to cointegration. The ARDL result confirmed the existence of a long-run relationship between Economic Growth, Trade Openness, Foreign Direct Investment and Gross Capital Formation. It was found that Trade Openness and Gross Capital Formation had positive and negative impacts respectively on growth rate of GDP in the short run. Therefore, this study concludes by recommending that; (i) trade openness should be regulated by government; from our result an increase in trade openness caused a decrease in our GDP (ii) FDI should be encouraged as it was seen to have significantly improved economic growth in Nigeria.