Detailed investigations on the electronic and magnetic properties of the Heusler compounds Mn2−xCuxVAl with L21 structure have been performed. Polycrystalline samples have been examined by X‐ray diffraction and magnetization measurements have been performed. The degrees of the B2 and L21 atomic ordering obtained from the intensity ratios of the X‐ray patterns have been determined. The Curie temperatures decrease with Cu content, ranging between 771 K (x = 0) and 580 K (x = 0.5). Additionally, electronic band structure calculations using the Korringa–Kohn–Rostoker (KKR) Green's function method have been performed. The substitutional disorder was accounted by the means of the Coherent Potential Approximation (CPA). The site occupation considered in the calculations has been correlated with those obtained by the X‐ray experiments. Our study is giving an insight on the evolution of the half‐metallic fully compensated ferrimagnet (HMFi) character with disorder and Cu doping showing restrictions in obtaining of a HMFi by doping with 3d metals.