This paper presents a numerical study on the inelastic local web buckling behaviour of top flange coped beams with welded end connections. The modelling strategy based on the finite element (FE) method was validated and calibrated using the test results obtained in previous experimental work. Subsequently, a comprehensive parametric study using the validated FE model was carried out to carefully examine the effects of various parameters on the inelastic buckling strength and behaviour of practical coped beams with a welded end plate connection. Evident inelastic buckling behaviour was observed in most of the FE models, except for those with web slenderness (d/tw) equal to 56.3 and cope length to reduced beam depth ratio (c/h0) equal to 1.0. The influence of initial geometric imperfection on the buckling strength and response was also investigated in detail. Based on the parametric study results, a design approach according to the ‘plate shear buckling model’ was proposed to evaluate the inelastic buckling strength of coped beams. It was shown that the proposed approach provided better predictions of the FE results when compared with those of the current design strategy.