Agricultural byproducts like wheat straw and distillers dried grains with solubles (DDGS) have not found a good market in the wood composite industry. Utilizing DDGS for particleboard in addition to using it as feed will add economic value. This study investigated the potential of using DDGS and wheat straw at different proportions in low-density particleboard with phenol-formaldehyde binder. The effect of alkaline pretreatment of DDGS and wheat straw on the properties of board was also studied. Particleboards were tested for physical and mechanical properties, including density, water absorption, thickness swelling, flexural, internal bond, screw withdrawal, and hardness properties. Particleboards with 25% DDGS loading and 75% wheat straw met most of the mechanical properties requirement for low-density particleboards. Alkaline pretreatment did not improve the properties of manufactured particleboards. This study suggests that a higher fiber fraction DDGS and wheat straw can be used in low-density particleboards with reduced synthetic resins.