Intellectual or knowledge-based capital is an intangible asset that does not appear on the balance sheets. It consists of human, structural and customer capital components, is measurable, and has been providing a competitive advantage to businesses. In the study, the intellectual capital-financial performance relationship of 102 Borsa Istanbul Industrial Index companies with available data is analyzed on the basis of sub-sectors, by panel data analysis method, for the years 2008-2015. The results show that intellectual capital has a positive effect on financial performance, companies attach importance to human capital, but structural capital is not yet at a sufficient level in enterprises. [ABSTRACT FROM AUTHOR]