This paper deals with analysis of symmetric laminated composite plates for critical buckling in biaxial loading. The minimum load at which the equilibrium is disturbed known as the critical buckling load. The study is focused on obtaining the critical buckling load of symmetric four layers laminated composite plate subjected to biaxial compressive loading, varying plate parameters a/b (aspect ratio) = 0.5 to 1 with 0.5 increment. Governing equations for buckling are derived based on Classical Laminated Plate Theory (CLPT) and computed critical buckling loads were compared with numerical results obtained using ANSYS the finite element software. The effect of aspect ratio is carried out to determine the variation in critical buckling loads.