This paper deals with frequency optimization of symmetrically laminated angle-ply annular circular plates. The design objective is the maximization of the fundamental frequency, and the design variable is the fiber orientation in the layers. The first-order shear deformation theory and nine-node isoparametric finite element model in polar coordinates are used in finding the natural frequencies. The modified feasible direction (MFD) method is used for the optimization routine. For this purpose, a program based on FORTRAN is used. Finally, the numerical analysis is carried out to investigate the effects of radius ratios, boundary conditions, and uniform external or internal pressure loads on the optimal designs, and the results are shown in tabular and graphical forms.