In this paper we empirically examine the impact of labor market flexibility on FDI flows to oil-rich GCC and compare it to middle income countries in 2006-2011. We account for potential endogeneity and nonstationarity and adopt system GMM and IV estimation methodologies. Our findings show that in middle income countries overall flexibility increases FDI flows under both system GMM and IV methodologies. In GCC countries overall LMF decreases FDI flows under system GMM methodology. Results also show a positive “GCC region” influence outweighing the negative flexibility influence. Growth potential and infrastructure development matter for both GCC and middle income countries.