The Companies Act 1985 (c. 6) is an Act of the Parliament of the United Kingdom of Great Britain and Northern Ireland, enacted in 1985, which enabled companies to be formed by registration, and set out the responsibilities of companies, their directors and secretaries.

The Act was a consolidation of various other pieces of company legislation, and was one component of the rules governing companies in England and Wales and in Scotland.

A company will also be governed by its own memorandum and articles of association.

Instead, it was introduced by statutory instrument - the Companies (Tables A to F) Regulations 1985.

Company law throughout the United Kingdom is now governed by the Companies Act 2006, which received Royal Assent on 8 November 2006, and which was commenced in stages between then and 1 October 2009.