Petroleum-based plastics and composites have caused serious environmental problems leading to the onset of an imbalance on the equilibrium of our ecosystem. At the same time, agricultural residues are produced in huge volumes all over the world, corresponding to more than 200 billion tonnes per year. These residues also cause significant environmental problems, for example they are often disposed by open burning. A more beneficial route would be to upcycle these residues for production of materials that can replace petroleum-based plastics. This chapter reviews selected agricultural residues and their utilization for production of biocomposites and bioplastics with high biobased content and potential biodegradability. In the case of biocomposites, mainly materials consisting of natural fibers from agricultural residues and polysaccharide-based matrices are highlighted, while biocomposites with synthetic biobased matrices or fossil-based non-degradable matrices are not discussed in this review. Finally, a brief outlook on future potential is presented.