The natural fiber composites have attracted much interest among the researchers, due to their low cost, easy availability and enhancement in their properties. Many plants based natural fibers, including banana, sisal, hemp, jute, oil palm, Coirand kenaf, among others, have been studied extensively. Sansevieria cylindrica fiber (SCF) is one of the plant-based leaf fibers, which has not been explored to a greater extent. The main purpose of this study focused on utilizing SCF as a potential reinforcement to produce polyester matrix composites. Unsaturated polyester resin was used as matrix, because of its low cost and ease of use. In this work, free vibration studies were performed for pure SCF reinforced polyester composites. The SCF composites were fabricated with various fiber percentage weight (wt%) and different curing temperatures. The effects of both fiber wt% and curing temperatures on natural frequency and damping of SCF composites were studied. It was observed that both natural frequency and damping showed significant variations on different process conditions of polymer composites. Based on vibrations studies, the optimum fiber wt% was obtained at 40 and optimum curing temperature was observed as 60 °C. Furthermore, the effects of various chemical treatments on vibration behaviors of SCF composites was also investigated for the optimum fiber loading and curing temperature of 40 wt% and 60 °C, respectively. Ca(OH)2 treated composite exhibited highest natural frequencies for all the three modes of vibration and silane treated counterpart showed highest damping values for the last two modes of vibration. Therefore, it was evident that chemical treatment significantly influenced the dynamic properties, including natural frequency and damping of SCF reinforced polyester composites. This study can guide the composites/manufacturing companies to design and manufacture composites for engineering system applications, especially where vibration response is inevitable.