Coarse-grained molecular dynamics simulations are used to investigate the adsorption behavior of monodisperse and bidisperse polymer chains on the nanoparticle (NP) surface at various polymer-NP interactions, chain lengths, and stiffness. At a strong polymer-NP interaction, long chains preferentially occupy interfacial region and squeeze short chains out of the interfacial region. Semiflexible chains with proper stiffness wrap NPs dominantly in a helical fashion, whereas fully flexible chains constitute the surrounding matrix. As chain stiffness increases, the results of the preferential adsorption are the opposite. The chain-length or chain-stiffness-induced selective adsorption behavior of polymer chains in the polymer-NP interfacial region relies on a delicate competition between entropic and enthalpic contributions to the total free energy. These results could provide insights into polymer-NP interfacial adsorption behavior and guide the design of high-performance nanocomposites. (C) 2016 Wiley Periodicals, Inc.