In this paper, the potentials of using particles, especially nanoparticles, in enhanced oil recovery isinvestigated. The effect of different nanoparticles on wettability alteration, which is an importantmethod to increase oil recovery from oil-wet reservoirs, is reviewed. The effect of different kinds ofparticles, namely solid inorganic particles, hydrophilic or hydrophobic nanoparticles, andamphiphilic nanohybrids on emulsion formation (which is cited as a contributing factor in crude oilrecovery) and emulsion stability is described. The potential of nanohybrids for simultaneously actingas emulsion stabilizers and transporters for catalytic species of in situ reactions in reservoirs is alsoreviewed. Finally, the application of nanoparticles in core flooding experiments is classified basedon the dominant mechanism which causes an increase in oil recovery from cores. However, thepreparation of homogeneous suspensions of nanoparticles is a technical challenge when usingnanoparticles in enhanced oil recovery (EOR). Future researches need to focus on finding out theproper functionalities of nanoparticles to improve their stability under harsh conditions of reservoirs.