System 4 is the code Rensis Likert gave to the future of organisations moving away from the bureaucratic model of Max Weber, which he referred to as System 1. Likert used a psychological analysis of organisations and conducted extensive research using questionnaires that try to locate the extent to which organisations are compliant with system 1, system 4, or in between.

System 4 is also the name given to a range of computers sold by English Electric Computers which was later to become International Computers Ltd. The System 4-50 and System 4-70 were essentially RCA Spectra 70 clones of the IBM System/360 range.