Biodegradable poly(L-lactide) (PLLA)/octavinyl-polyhedral oligomeric silsesquioxanes (ovi-POSS) nanocomposites were prepared via solution and casting method at low loadings of ovi-POSS in this work. Effect of ovi-POSS on the crystallization behavior, spherulitic morphology, crystal structure, and thermal stability of PLLA in the nanocomposites was investigated in detail. It is found that both non-isothermal melt and cold crystallization of PLLA in the nanocomposites are enhanced by the presence of ovi-POSS. In addition, the enhancement becomes more significant with the increase of POSS content to 1 wt%. For isothermal melt crystallization, the overall crystallization rates are faster in the PLLA/ovi-POSS nanocomposites than those in neat PLLA and improved with increasing the ovi-POSS loading; however, the crystallization mechanism and crystal structure of PLLA remain unchanged despite the presence of ovi-POSS. The thermal stability of PLLA in the PLLA/ovi-POSS nanocomposites is reduced slightly relative to neat PLLA. (C) 2011 Elsevier B.V. All rights reserved.