Numerical investigation of the flexural behaviour of an innovative sandwich composite panel is presented. The panel consists of outer structural plywood skins and an inner core of vertically aligned hollow bamboo rings and is referred to as Bamboo Core Sandwich (BCS). The flexural behaviour of the BCS panel under one-way and two-way bending is investigated using the Ritz-method. The Ritz-model is validated against published results of an experimental test conducted on GFRP sandwich panels. The effects of the thickness of the plywood skins and height of the bamboo core on the bending stiffness of BCS panels are presented. The results are compared to the bending stiffness of Cross-laminated Timber (CLT) panels of almost similar depths. Results indicate that at almost identical bending stiffness, the proposed sandwich composite panel can be thinner and substantially lighter than existing commercial CLT panels.