This paper deals with the free vibration characteristics of woven fiber glass/epoxy delaminated doubly curved composite panels in a thermal environment based on the finite element approach. First-order shear deformation theory is used for a composite shell model with provision of mid-plane strip delamination at arbitrary locations. An isoparametric quadratic shell element with eight nodes and five degrees of freedom per node is used in the analysis. For modeling the delamination, a multipoint constraint algorithm is incorporated in the analysis. The thermal field includes elevated temperatures up to 400 K and sub-zero temperatures up to cryogenic range of 123 K to simulate the temperature surrounding the aircraft during flight and ground conditions and submarines. The effects of delamination size, temperature, boundary conditions and curvature on the natural frequencies of composite panels are investigated. The results indicate that the percentage of strip delamination, curvature with different boundary conditions in a thermal field have significant effects on the vibration behavior of the composite panels.