A new micromechanical approach for predicting the compressive response of long fiber composites based on a periodic unit cell model with a centrally located imperfection is presented. A detailed comparative analysis between the proposed model and the existing models was performed at the macro and micro level. The results show that the periodic unit cell model with non-uniform fiber waviness is able to reproduce the mechanisms that govern the failure of fiber-reinforced polymers under compression and provide accurate characteristics of microbuckling.