Wheat straw was used as raw material in production of medium density fibreboard (MDF) and high-density fibreboard (HDF). The straw fibreboard process was performed without addition of synthetic binders. Adhesive bonding between fibers was initiated by activation of the fibre surfaces by an oxidative pre-treatment in the defibration process. Hydrogen peroxide was added into the blowline to get a fast and effective process. Adhesive bonding between the activated fibres were later formed when pressing. The fiber quality and pH and pH buffering capacity was analysed at different hydrogen peroxide loadings. The effects of mechanical and physical properties of the non-resin wheat straw MDF/HDF were evaluated. Mechanical bending properties, Modulus of Rupture (MOR), Modulus of Elasticity (MOE), and Internal Bond (IB) were generally lower than conventional wood-based MDF/HDF but close to the requirements of the MDF-standard. Modulus of Elongation (MOE) was surprisingly high and exceeded the levels in the MDF-standard. Moreover, the thickness swelling of the non-resin wheat straw MDF was high but was reduced by the addition of a hydrophobic agent (metallic ion). Increased level of hydrogen peroxide improved the panel properties and the usage of the hydrophobic agent reduced the thickness swelling.