The growing interest in the knowledge economy raises many questions about its effect on economic growth. The study aims to position a set of MENA countries in the context of the knowledge economy compared to developed countries. It also detects theoretically and empirically the knowledge effect on economic growth. To do this, the authors have estimated an endogenous growth model, using the dynamic panel data technique, for a sample of 16 MENA countries over 1995-2014. The results show that, despite the significant improvements that have registered in the knowledge economy pillars, the selected countries are still lagging compared to developed countries. Far from international comparisons, the internal effects of these knowledge pillars (education, innovation, ICT, institutional regime) on growth are positive and highly significant.