As compared to conventional mechanisms, compliant mechanisms exploit flexible deformation rather than rigidbody motion of its components. The key advantage of jointless or monolithic structures lies in the absence of relative motion between the links. Besides the reduction in parts required to perform a task, compliant mechanisms typically show little friction, if any, and do not require lubrication to minimize wear. On the downside, design and synthesis of compliant mechanisms become much more involved than in rigidbody linkages. In particular, optimization of compliant mechanisms relying on (sub)structures subjected to large flexible deformation is a challenging task, in which diverse aspects need to be considered. First and foremost, kinematic analysis of compliant mechanisms usually requires geometric nonlinearities to be accounted for. Further, limitations in actuation forces and torques impose constraints on the design. Depending on the application, the performance of compliant mechanisms may crucially depend on the natural frequencies and their change over the range of operation. In view of the diverse aspects, one typically has to deal with multiobjective optimization problems in comparatively highdimensional parameter spaces.