The infrared‐absorption spectra of commercially available SiC whiskers were measured. The spectra were dominated by the small particle resonances associated with finite ionic crystals. Analysis of these resonances allowed characterization of both morphological and electronic properties of the whiskers. The data were analyzed using Rayleigh and Mie theories as well as an effective medium model based on the Maxwell–Garnett approximation. It was possible to determine whisker radius and identify whiskers with a high free‐carrier density and a core‐shell structure. The effects of decreasing aspect ratio were also studied. The results showed that infrared‐absorption spectroscopy provides an effective and relatively simple means to characterize SiC whiskers.