In theory, the foreign direct investment and environmental pollution nexus is explained by three hypotheses. Firstly, pollution haven hypothesis assumes that there is a positive nexus between these variables. Secondly, pollution halo hypothesis supposes that there is negative connection between these variables. Lastly, neutrality hypothesis asserts the non-existence of the connection between these variables. In recent years, many researchers have frequently tested whether these hypotheses are valid for different countries. In this study, applying Westerlund panel cointegration test, the authors aim to explore the nexus between foreign direct investment and environmental pollution for 23 developing countries after global crisis. For this aim, they use annual data covering the period 2009-2019. According to the obtained empirical findings, the presence of the long-term nexus between foreign direct investment and environmental pollution is not detected for 23 developing countries. Accordingly, the authors can say that there is neutrality hypothesis.