Current research studies have been focusing on the procurement of environmentally friendly materials, with the aim of resolving the problems created by materials derived from petroleum. Starch is a promising biopolymer for producing biocomposite materials because it is renewable, completely biodegradable, and easily available at a low cost. Thermoplastic starch (TPS), by itself, exhibits poor mechanical properties such as low tensile strength and severe deformations, which limits its application in packaging or films. In addition, TPS presents high hygroscopicity. The use of reinforcing agents in the starch matrix is an effective means to overcome these drawbacks and several types of biodegradable reinforcements, such as cellulosic fibers, whiskers, and nanofibers, have been utilized to develop new and inexpensive starch biocomposites. This chapter provides the latest advances in green composite materials based on TPS and cellulose fibers and includes information on compositions, preparations, and the properties of "green" composite materials elaborated from TPS and cellulose fibers, with the focus on using undervalued natural resources.