Regulation is the management of complex systems according to a set of rules and trends. In systems theory, these types of rules exist in various fields of biology and society, but the term has slightly different meanings according to context. For example:

• in biology, gene regulation and metabolic regulation allow living organisms to adapt to their environment and maintain homeostasis;
• in government, typically regulation refers to the delegated legislation which is adopted to enforce primary legislation;
• in business, industry self-regulation occurs through self-regulatory organizations and trade associations which allow industries to set and enforce rules with less government involvement; and,
• in psychology, self-regulation theory is the study of how individuals regulate their thoughts and behaviors to reach goals.