An agreement made between the shareholders of a company and, in some cases, the company. It can arise in a number of situations:
In a private limited company with multiple shareholders to set out, amongst other things, terms governing the relationship between the parties, issue and transfer of shares and directorships. See Standard document, Shareholders' agreement between individuals.
In a joint venture to deal with the ongoing relationship of the joint venturers as shareholders in the joint venture company, and covering such issues as appointment of directors, distribution policies and reserved matters for shareholders. See Joint ventures toolkit.