Abstarct: This study investigates the elastoplastic analysis of rotating disks with variable thickness made of functionally graded materials (FGMs), employing Tresca’s yield criterion to identify plastic regions. First, the governing equations describing the behavior of rotating annular disks are developed baxsed on the elastic response of the material. Subsequently, by applying Tresca’s yield criterion along with the elastic–perfectly plastic flow rule, the displacement equations and stress distributions within the plastic zone are derived. To examine the influence of the disk profile on the stress distribution and plastic behavior, it is assumed that the thickness of the disk section varies exponentially with the radius. Furthermore, this research explores the evolution of plastic flow, focusing on how and where the yielding process initiates within the disk. In other words, the study aims to determine the regions where yielding begins and how these regions expand under the effects of thickness variation and material properties. The obtained results are compared with previously reported findings for homogeneous disks (with uniform material composition throughout) and FGM disks of constant thickness, showing good agreement. This comparison confirms the reliability of the proposed model. Finally, the findings demonstrate that considering variable thickness has a significant effect on the stress distribution across the disk and alters the location where yielding starts. Specifically, thickness variation can influence the intensity of stresses and the development of plastic zones, thereby providing valuable insights for predicting the behavior of rotating disks under different loading conditions.