In this work, the critical buckling behavior of haunched steel plate girders subjected to shear loading is investigated in depth. The study is conducted through linear buckling analysis using the finite element method. First, the results are validated with previous results for simply supported rectangular and nonrectangular web panels. Thereafter, an extensive parametric study is conducted to investigate the influence of various geometric parameters including the inclination angle, the panel aspect ratio, the size of the flanges and the presence of longitudinal stiffeners on the buckling coefficients. Finally, the results are employed to develop expressions for the shear buckling coefficients for longitudinally stiffened-haunched steel plate girders taking into account the forementioned parameters.