This paper contains the results from three different methods for determining deflections and stress resultants of thin laminated composite plates subjected to lateral loads and uniform temperature changes. The first method is a classical method using the method of Ritz, and the results are considered exact; however, this method is cumbersome and not practical. The other two methods are more practical but in many instances produce approximate results. Each of these two simplified methods reduces the composite to a single orthotropic layer which is “equivalent” to the composite. The results from the two simplified methods are compared with the results from the exact method.