This paper presents an experimental investigation of pultruded glass fibre reinforced polymer (GFRP) circular hollow section (CHS) columns under concentric and eccentric compression. The member slenderness of the selected columns was in the short, intermediate, and long range, and two different eccentricities were chosen within the column's cross section. Predominant failure modes observed in the experiment include longitudinal splitting and localized delamination buckling. The load-carrying capacities of the concentric column under different slenderness values were quantified and compared with existing design rules. Under eccentric loading, the ultimate loads of the columns decrease with increasing eccentricity and slenderness, and the load–strain behaviour displayed non–linear characteristics due to geometric non-linearity. Failure modes of all the tested columns were well predicted by the FE models, and it was found that splitting material failure was due to hoop matrix tensile rupture.