The isothermal and nonisothermal crystallization behavior of high density polyethylene (HDPE) containing various zero, one, and two dimensional (0-D, 1-D, and 2-D) carbon nanofillers were investigated by means of differential scanning calorimetry. For a given temperature, the isothermal crystallization incubation time of HDPE became longer with the addition of lower dimensional carbon nanofillers, and the isothermal crystallization rate got slower. The values of Avrami and Tobin exponents indicated that the isothermal crystallization of HDPE followed two-dimensional crystal growth in the presence of 2-D and 1-D carbon nanofillers, while exhibited three-dimensional heterogeneous crystal growth in the presence of 0-D carbon nanofillers. Contrary to the isothermal study, the nonisothermal crystallization of HDPE was accelerated in the presence of lower dimensional nanofillers. The nonisothermal crystallization data were finally analyzed using Ozawa and Mo methods. It was observed that only Mo approach could successfully describe the nonisothermal crystallization process of HDPE and HDPE/carbon nanocomposites. (c) 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013