Benzoxazine resins and poly(epsilon -caprolactone) (PCL) are melt blended and the properties of the blends in the range of 0-15 wt.% of PCL are studied by dynamic mechanical analysis (DMA) and thermogravimetric analysis (TGA). The T(g)s of the benzoxazine blends in the presence of PCL are found to be slightly lower than that of neat polybenzoxazine resin. The blends show improved mechanical properties, including higher crosslink densities, rubbery plateau moduli, and flexural strengths compared to pure polybenzoxazine. Moreover, the thermal stabilities at middle temperature range in the presence of PCL modifiers are also enhanced, which is evident from the delayed onset decomposition temperature and the disappearance of the first degradation event.