Abstract: Closed-form expressions considering the influence of single or multiple rectangular holes on the critical elastic buckling stress of plates under bending, compression, shearing and combined bending shear are developed, validated and summarized. The expression forms are based on classical plate stability approximations, and are developed and verified by parametric studies employing shell finite elements. The expressions serve as a convenient alternative to shell finite element eigen-buckling analysis. The finite element parameter studies show that holes may produce unique buckling modes, and the change of hole spacing may reduce or increase the critical elastic buckling stress of the plate. When the spacing between holes is long enough, the buckling stress equation of single-hole plate can be used for multiple-hole plate. The validated closed-form expressions and their associated limitations are intended to be versatile enough to accommodate the range of hole sizes and spacings commonly found in engineering practice.