Cellulosic fibers having enhanced reversible thermal properties and methods of forming such cellulosic fibers are described. In one embodiment, a cellulosic fiber includes a fiber body formed of an elongated member. The elongated member includes a cellulosic material and a temperature regulating material dispersed within the cellulosic material. The temperature regulating material includes a phase change material having a transition temperature in the range of −5° C. to 125° C. The cellulosic fiber can be formed via a solution spinning process and can be used in various products where thermal regulating properties are desired. For example, the cellulosic fiber can be used in textiles, apparel, footwear, medical products, containers and packagings, buildings, appliances, and other products.