This PhD project aims to identify and quantify the key factors that influence adhesive strength in bio-based adhesive systems. It focuses on understanding how adhesive chemistry, wood surface characteristics, and bonding conditions interact to affect both strength and durability. The research combines mechanical testing methods, such as tensile shear and compressive Strength, with material characterization techniques like microscopy and contact angle analysis to examine the adhesive–adherent interface. A key objective is to connect laboratory-scale results with real-world performance, improving the ability to predict how bio-based adhesives will behave in practical applications. We hope the outcomes will support the development of more consistent, reliable, and sustainable adhesive solutions for engineered wood products.