The　nonlinear　oscillations　and　chaotic　dynamics　are　studied　for　a　simply-supported　symmetric　cross-ply　composite　laminated　rectangular　thin　plate　with　parametric　and　forcing　excitations.　Based　on　the　Reddy＇s　third-order　shear　deformation　plate　theory　and　the　von　Karman　type　equation,　the　nonlinear　governing　partial　differential　equations　of　motion　for　the　composite　laminated　rectangular　thin　plate　are　derived　by　using　the　Hamilton＇s　principle.　The　governing　equations　get　reduced　to　ordinary　differential　equations　in　thickness　direction　with　variable　coefficients　and　these　are　solved　by　the　Galerkin　method.　The　case　of　1:2:3　internal　resonance　is　considered.　The　method　of　multiple　scales　is　employed　to　obtain　the　six-dimensional　averaged　equation.　The　stability　analysis　is　given　for　the　steady-state　solutions　of　the　averaged　equation.　The　Numerical　method　is　used　to　investigate　the　periodic　and　chaotic　motions　of　the　composite　laminated　rectangular　thin　plate.　The　results　of　numerical　simulation　demonstrate　that　there　exist　different　kinds　of　periodic　and　chaotic　motions　of　the　composite　laminated　rectangular　thin　plate　under　certain　conditions.　©　2011　IEEE.