This chapter discusses various mechanical joining processes and the joining processes that offer mechanical interlocking like adhesive bonding. The mechanical joining processes play a key role in pressure vessel fabrication, truss construction, and in aircraft, automobile, and ship building sectors. Temporary joining of components is performed by mechanical fasteners like threaded fasteners, pins, and clips. The chapter describes permanent mechanical joining processes like mechanical fastening processes, clinching, joining by forming methods, joining by fits, and adhesive bonding. Self-pierce riveting (SPR) is a one-step mechanical joining process which is used for joining metallic sheets, multi-sheet material combination, and plastics. Although SPR is suitable for joining dissimilar materials, their ductility plays a vital role in deciding the joint fabrication without cracks occurring during joining. Mechanical clinching is used for joining similar and dissimilar sheet materials like SPR. This process is successfully used in automobile industry.