Study on non-isothermal crystallization kinetics of polymer is relevant for both fundamental as well as application perspective. Hence, the non-isothermal crystallization kinetics of bulk and confined poly(ethylene oxide) (PEO) in electrospun nanofibers was investigated using DSC. The nanofibers were prepared from polystyrene (PS)/PEO immiscible blends where PEO weight fraction was varied upto 0.4. It was found that the Avarmi and Jeziorny models successfully predict the nucleation nature of PEO chains and its growth behavior. However, the Ozawa model was not found to be suitable for the confined system. Nevertheless, the Mo's method, which is the combination of Avrami and Ozawa models, effectively described the non-isothermal crystallization behavior of PEO in confined domains. The Kissinger and Takhor methods showed that activation energy for crystallization of PEO chains increased with reduction of PEO weight fraction in the nanofibers. This was plausibly due to the geometrical restriction on the mobility of PEO chains. The present study is the first report on non-isothermal crystallization behavior of confined polymer in electrospun nanofibers systems.