The objective of the study presented in this paper is to expand the understanding of the compression behaviour of square concrete columns internally reinforced with Glass Fiber Reinforced Polymer (GFRP) bars. A total of six columns were tested with the test variables being the type of internal reinforcement (steel bars and GFRP bars) and magnitude of load eccentricity. Results from this study showed that GFRP reinforced columns achieved a lower load carrying capacity as compared to the steel reinforced column specimens for both concentric and eccentric loading conditions. The load carrying capacity of the concentrically loaded GFRP reinforced column was 4.8% lower than its steel counterpart; whereas the load carrying capacity of the eccentricity loaded GFRP reinforced specimens were on average 18.5% lower than their steel counterparts. In addition, the eccentrically
loaded GFRP columns achieved an increase in load after concrete spalling unlike the steel reinforced columns.