The Institution of Mechanical Engineers (IMechE) is an independent professional association and learned society headquartered in London, United Kingdom, that represents mechanical engineers and the engineering profession. With over 120,000 members in 140 countries, working across industries such as railways, automotive, aerospace, manufacturing, energy, biomedical and construction, the Institution is licensed by the Engineering Council to assess candidates for inclusion on its Register of Chartered Engineers, Incorporated Engineers and Engineering Technicians.

Mechanical engineering is the study of physical machines that may involve force and movement. It is an engineering branch that combines engineering physics and mathematics principles with materials science, to design, analyze, manufacture, and maintain mechanical systems. It is one of the oldest and broadest of the engineering branches.