Results are presented on the strength and deformation capacity of concrete transversely reinforced with fibreglass filaments (wires). A total of 33 cylinders confined with fibreglass wires were tested to obtain complete stress–strain curves in compression. The wires were 80% glass and 20% polyester resin matrix, and had a tensile strength of 300 ksi (2070 MPa). Based on the experimental data, an analytical equation was developed to predict the stress–strain curves of plain and fibreglass wire–confined concrete. The two constants in the equation were calibrated from the observed test results, so that only the strength of concrete was required to generate the stress–strain response of plain concrete, and the strength of plain concrete and the spacing of the fibreglass wires were required to generate the complete stress–strain response of fibreglass–confined concrete. Results of this study are compared with those reported for concrete confined transversely by steel reinforcement.