The influence of square opening sizes on the shear behaviour of hollow tubular flange plate girders is investigated herein. Accordingly, a three-dimensional finite-element model using Abaqus has been employed. The results of the hollow tubular flange plate girders with web openings are compared with equivalent I-section plate girders with flat flanges with openings which have been examined extensively in the literature. The results indicated that employing the hollow tubular flange plate girders with web openings instead of the corresponding I-section plate girders is a high-performance solution for the drop in shear owing to the presence of these openings. Additionally, it is found that there is no need to check the local stresses existing around the openings at the serviceability limit state for hollow tubular flange plate girders with web openings because any local yielding will have a limited effect on deflection. It is furthermore found that the design strength of hollow tubular flange plate girders should consider the sum of the contributions of both the web and the hollow flanges.