The study investigates the flexural behaviour and ductilities of reinforced concrete (RC) T-beams strengthened with perforated steel plates. A total of eight full-scale RC T-beams were tested. Three strengthened beams and a reference unplated beam were reinforced with closely spaced stirrups, while the remaining plated beams and reference beam did not have adequate amounts of shear reinforcement (shear deficient). Shear strengthening with post-tensioned anchors was found to shift the failure mode of a shear-deficient beam from shear to flexure. The post-tensioning forces in the anchors were established to be kept at an optimum level to provide adequate shear strength to the beam and to prevent overstraining of the soffit plate between the shear anchor locations. The perforations increased the ductilities, energy absorption capacities and permanent deformations of the specimens. The use of compression plate in addition to the tension (soffit) plate greatly contributed to the ductilities of specimens with adequate and inadequate shear strength.