Trade union

Trade unions—also called labour or labor unions—are organizations formed by workers to represent shared interests in dealings with employers. They may be organized around a trade or occupation, a workplace, an industry, or another membership basis. Their internal rules and structures vary, but member representation and collective voice are central features. A union's role is shaped by the sector and by the legal and economic environment in which it operates.

A major union activity is collective bargaining: negotiation between workers' representatives and employers or their organizations over employment terms. Agendas can include wages, working hours, training, occupational health and safety, equal treatment, benefits and other workplace conditions. Negotiations may result in a collective agreement setting out terms as well as the parties' responsibilities. Unions may also represent members in workplace discussions or disputes. Bargaining arrangements can cover a single employer or extend across a sector, and their scope differs among countries.

Although workers formed associations before the modern union movement, organized trade unionism expanded during the nineteenth century as industrialization changed work and employment relations. It developed in different ways in Britain, continental Europe, the United States and elsewhere. Some unions initially organized skilled workers by craft; later movements also organized workers across industries. The movement's history is not a single sequence: unions have differed in their political relationships, strategies, membership and influence, and the balance between collective bargaining and other forms of worker representation has changed over time.

International labour standards address workers' freedom to organize and the protection of collective bargaining. The International Labour Organization's Freedom of Association and Protection of the Right to Organise Convention (No. 87) and Right to Organise and Collective Bargaining Convention (No. 98) are central instruments in this area. Their application depends on national law, ratification and enforcement; rules on union recognition, bargaining coverage, public-sector workers and industrial action are not identical everywhere. The OECD notes that labour relations and collective-bargaining systems vary across countries and have been affected by changes in employment and the wider economy. A union's presence therefore does not guarantee a particular bargaining outcome: its practical influence depends on its members, employers, institutions and the applicable law.