Oxide nanofibers synthesized by the electrospinning method have received considerable attention owing to their potential applications in various fields. This paper provides an overview of the growth behavior and the importance of the presence of nanograins in oxide nanofibers synthesized by the electrospinning method. The growth behavior of nanograins in various oxide nanofibers is described in terms of its effect on activation energy and growth exponent, which are then compared with the bulk counterparts. The lower activation energy of nanograins in nanofibers by an order of magnitude revealed that the active participation of nanograins during grain growth is due to higher chemical potential of atoms presented in nanosized grains. In addition, the influences of nanograins on the electrical, gas-sensing, magnetic, optical, and photocatalytic properties of nanofibers are discussed. It is shown that optimization of the nanograin size is essential to ensure that the advantages of oxide nanofibers are utilized in different applications.