Besides wood, the most widely used natural structural material, dicotyledonous fibre plants such as flax or hemp, and monocotyledonous grasses such as cereal straw or bamboo have been shown to be suitable for application in materials. Common reed is a less well-characterised plant resource in this regard. Therefore, common reed stems were characterised in uniaxial tension in the present study, aiming at acquiring basic information about the mechanical characteristics of this material. Furthermore, laboratory-scale composite beams were manufactured and tested in bending. Compared to wood species with similar density, common reed stem walls showed a comparable average modulus of elasticity of 8 GPa and a very good average tensile strength of 150 MPa. After a mild alkali pre-treatment, reed showed excellent adhesive bonding, enabling the manufacture of high-density composite beams with roughly 130 MPa bending strength and 12–13 GPa modulus of elasticity. Same as untreated common reed stem walls, also reed biocomposite beams compared very favourably with established wood-based materials of similar structure, density, and adhesive content. In summary, it was thus demonstrated that common reed is a highly suitable raw material for bio-based load-bearing structural materials.