Non-linear transient response of fluttering stiffened composite plates subject to thermal loads has been analyzed. The first order shear deformable plate and Timoshenko beam theories are used for the finite element modelling of a skin panel and stiffeners considering von Karman non-linear strain-displacement relationships. A supersonic piston theory is used for modelling aerodynamic loads. In order to find a critical flutter speed, linear flutter analysis of stiffened laminated panels considering large aero-thermal deflections has been performed. The flat and stable motion, limit cycle oscillation, and buckled but dynamically stable and chaotic motion of stiffened laminated panels have been investigated using the implicit Newmark integration method. Results show that the increase of the height and number of stiffeners to reduce an aero-thermal deflection can dramatically drop the boundaries of a dynamic stability at a certain point. Also, the non-linear behaviors, such as dynamically stable motions with static aero-thermal deflections, limit cycle oscillations, periodic motions with large amplitude and chaotic oscillations, are observed in the time domain analysis. (C) 2001 Academic Press.