The change in platelet shape is an active, dynamic, and complex process crucial for activation and platelet functions and primary hemostasis. Physical or chemical factors can trigger the morphological change in platelets. Platelet receptors, membranes, and the cytoskeleton play vital roles in this shape change; any mutations in platelet structure or dysregulation of this process can result in platelet dysfunction and various disorders. The shape change of platelets can be detected using different methods for in vitro assessment, including macroscopic, microscopic, and advanced techniques such as flow cytometry, as well as in vivo assessments in animal models through intravital microscopy. In this chapter, we reviewed the morphological changes of platelets step by step, from their disc shape to clot formation. We also discussed the activation of platelet components, particularly the cytoskeleton and its parts. Additionally, we briefly explained how laboratory methods detect changes in platelet shape and the platelet disorders associated with these shape changes.