It is needed to establish a design capacity curve of beams/columns with RC standing, hanging and wing walls for utilizing such walls as structural members in RC buildings in Japan. This paper presents the results of static loading tests on RC beam-column sub-assemblages with such walls, which were conducted to evaluate their strength, ductility, stiffness and damage. The flexural yield strength of beams with the walls can be well estimated by a flexural analysis assuming the plane section remain plane. The flexural ultimate strength can be accurately estimated at the full plastic moment. The proposed method, which is a modification of a practical design method in a distance from the centre of tensile reinforcements to the extreme compression fibre, can evaluate the secant stiffness at the yield point more precisely than the practical design method.