Abstract: Structural insulated panels, commonly known as SIPs, are a panelized building system composed of external oriented strandboard wood sheets bonded to a lightweight boardstock or pour-in-place foam core. This paper describes a combined experimental and analytical study whose objective was to investigate the structural behaviour of OSB-faced SIPs subject to short-term out-of-plane transverse loading. A total of 35 panels with varying types of foam core, thickness and other construction details were subjected to partially distributed uniform loading. The results showed that the ultimate shear resistance of SIPs is proportional to the mechanical properties of the core material, and inversely proportional to the thickness of the core. The observed relationship between core shear stress at failure and core thickness was used to calibrate a reliability-based design expression to predict the shear strength of full-size panels based on properties obtained from small-scale foam material tests. Finally, recommendations regarding panel design and construction are made to improve the shear behaviour of SIPs.