Malaysia produces a large amount of oil palm biomass yearly especially in the form oil palm trunks. The purpose of this research was to convert oil palm trunk waste into value-added panels namely particleboard. Binderless particleboards and particleboards with addition of 10% urea formaldehyde were made from oil palm trunk particles at higher thickness levels. Particleboards were manufactured at two thickness levels namely 10 mm and 15 mm at target density of 0.8 g cm−3. Physical and mechanical properties of particleboards including density, thickness swelling, water absorption, modulus of rupture and internal bond strength were determined. Moreover, properties of oil palm trunk particleboard were characterised in terms of thermal analysis by thermogravimetric analyses (TGA) and morphological analysis by scanning electron microscopy (SEM). Based on the results obtained, particleboards with addition of urea formaldehyde exhibited higher physical and mechanical properties in comparison to binderless particleboards at each thickness levels. On the other hand, particleboard of 10 mm in thickness showed better properties than particleboards of 15 mm in thickness except for modulus of rupture. The mechanical properties of all types of boards have met the minimum requirement of Japanese Industrial Standard for Type 8. The overall results revealed that addition of minimal amount of urea formaldehyde as adhesive can improve the basic properties of oil palm trunk particleboard.