This paper presents experimental tests, numerical simulations, and design methods on steel equal-leg angles subjected to compression. In the experimental programme, a total of 30 steel angles, with different depths of local defects produced at the mid-height, were loaded by a compression force on one leg. Two slendernesses of steel angles were selected in the design of specimens, and the location of local defects were placed at the inner face of the loaded leg and the inner and outer faces of the unloaded leg. The applied compression force and the associated deflections at the mid-height of steel angles were measured during testing. Besides, longitudinal strains of sections at the mid-height, top and bottom ends of steel angles were also measured to gain insight into the development of failure pattern. Comparisons were made among steel angles in terms of the ultimate load and the associated deflection to investigate the effects of slenderness, the location and depth of local defects. Numerical models are also developed for steel equal-leg angles in compression, in which residual stresses and initial geometric imperfections are considered. The validated numerical model is then used to conduct parametric studies on slenderness and local defect on the load capacity of steel angles. Based on the results of the parametric study, a design equation to calculate the ultimate load-carrying capacity of corroded steel angle is proposed. Comparisons with experimental results show that the design equation can calculate the ultimate load-carrying capacity of steel angle with local defects with good accuracy. •Ten groups of steel angles with local defects at the mid-height were tested under compression on one leg.•Numerical models are developed for steel angles in which residual stresses and initial geometric imperfections are considered.•Design equations are developed to calculate the load capacity of steel angles.