The linear and non-linear dynamic behavior of plates at elevated temperatures are examined. Analytical solutions for the buckling and post-buckling behavior are obtained. A general formula is then presented which links the fundamental frequency of vibration to the critical buckling temperature and the corresponding frequency of the unheated plate. The behavior of certain visco-elastic plates is also considered and a criterion for thermal buckling is presented. The analysis may be interpreted as an extension of Williams analysis of long narrow plates, for plates of finite aspect ratio.