Restraint of trade describes any contractual restriction on a person’s freedom to carry on a business, profession or employment, such as non-compete, non-solicitation and non-dealing clauses in employment, partnership, shareholder or commercial agreements. In England and Wales, Scotland and Northern Ireland, it is a common law doctrine developed in case law, under which restraints of trade are prima facie void unless they protect a legitimate business interest (for example, confidential information, customer connections or workforce stability) and go no further than is reasonable between the parties and in the public interest. Reasonableness is assessed by reference to scope, duration, geography, and the parties’ bargaining power. In Ireland, similar common law principles apply, informed by Irish case law and constitutional protection of freedom to work and trade. Across all four jurisdictions, restraint of trade issues typically arise in drafting and enforcing restrictive covenants, sale of business agreements, and franchise or distribution contracts. The doctrine is distinct from, but interacts with, statutory competition law, which may separately invalidate anti-competitive restrictions.