We review recent progress in the area of theoretical investigations of light-harvesting processes. The ap-plication of time-dependent density functional theory (TDDFT) in the calculation of excitation energy trans-fer coupling factor will be emphasized. The effect of a dielectric environment can be obtained through a re-sponse theory based on TDDFT formalism. As an example of applicability of TDDFT, the role of a transition forbidden S 1 state of carotenoid in a light-harvesting complex LH2 is discussed in detail. The applicability of TDDFT to states with charge-transfer character is also discussed with a few examples in the literature. Finally we briefly review works on the applications of TDDFT for excitations in chlorophylls and bacteriochloro-phylls.