The influence of bending-torsional coupling on the buckling load of general orthotropic, midplane symmetric and elastic plates has been studied. First this effect has been analysed for the case of infinitely long plate strips, resulting in approximate analytical solutions, which can be presented graphically for the entire range of the elastic constants. These solutions have been obtained with the approximate method as applied by W. Thielemann. To check the validity of these results for design purposes, they have been evaluated in comparison with results for finite length panels as derived with the finite element method. From this comparison the conclusion can be drawn that buckling loads for plates with aspect ratio over 2 or 3, which demonstrate the bending-torsional coupling effect, can be estimated fairly well from the results for the infinitely long plate strip.