This study aims to extend the Fama-French three-factor model by including human capital as a fourth factor. For this purpose, we have collected data from 164 non-financial firms from July 2010 to June 2020. To evaluate the validity and applicability of our augmented human capital-based four-factor model, we apply the two-pass time series regression proposed by Fama-Macbeth (1973). We find that small firms outperform big firms, value stocks firms outperform growth stocks firms, and low-labor-income firms outperform high-labor-income firms. The augmented human capital-based four-factor model is valid and applicable in the context of the Pakistan equity market. The empirical results motivate academia and all investors to consider human capital in investment decisions.