In this paper, the influence of initial geometrical imperfections on thermal stability of laminated composite plates using Layer wise plate model is presented. The mathematical model assumes layer wise variation of in-plane displacements, non-linear strain-displacement relations (in von Karman sense) and linear thermo mechanical material properties. The Koiter’s model for initial geometrical imperfection is adopted. Principle of virtual displacements (PVD) is used to derive Euler-Lagrange differential equations of linearized buckling problem. The weak form is discretized using nine-node Lagrangian isoparametric finite element. The original MATLAB program is coded for finite element solution. The effects of imperfection mode and amplitude, temperature distribution, side to thickness ratio b/h, aspect ratio b/a, boundary conditions and lamination scheme on critical buckling temperature are analysed. The accuracy of the numerical model is verified by comparison with the available results from the literature and new results are presented.