A trade union is an organisation formed by workers to represent and advance their collective interests in relation to employment. Trade unions can negotiate with employers over wages and working conditions, represent members in workplace disputes, provide advice and support, campaign for changes to labour law and participate in collective bargaining. Membership is normally voluntary, although the legal relationship between union membership and employment varies between jurisdictions.
Trade unions can represent workers within a particular employer, occupation, industry or broader labour market. They may operate at local, regional, national or international levels and can be affiliated with larger union federations. Their functions have expanded beyond wage negotiation to include health and safety, equality, job security, training, professional interests and political or public campaigns concerning employment policy.
The collective function of a trade union arises from the principle that workers can achieve greater bargaining power by acting together. Individual employees may have limited influence over employment terms because employers generally control recruitment, work allocation and many workplace resources. A union can aggregate members' interests and negotiate collectively.
Collective bargaining is one of the most important union activities, but representation also includes handling grievances, accompanying employees in disciplinary proceedings, advising members about contractual rights and supporting workplace health and safety. A union may also provide legal assistance or specialist advice depending on its resources and rules. Through these functions, unions can alter the balance of power within employment relationships by giving workers an organised institution through which to express collective interests.
Trade unions have historically developed alongside industrialisation and the growth of wage labour. During the nineteenth century, workers in many industrialising countries formed associations to respond to long hours, low wages, unsafe working conditions and limited individual bargaining power. Early unions often faced legal restrictions, employer opposition and difficulties organising workers across large workplaces. Over time, labour law in many countries established greater legal recognition of association, collective bargaining and industrial action.
Union organisation subsequently expanded beyond traditional industrial occupations into public services, transport, manufacturing, clerical work and professional employment. The history of trade unionism differs substantially between countries because political institutions, legal systems, industrial structures and employer practices have shaped the development of collective organisation in different ways.
Trade unions can have different organisational structures. A workplace branch may organise members within a particular employer, while a larger union may represent workers across many workplaces or occupations. Unions may have elected representatives who deal with management locally, alongside national officials responsible for negotiations, legal affairs, research, campaigning and administration. Some unions organise primarily by occupation, while others organise workers across multiple occupations within an industry or employer. Union federations can coordinate activities among separate unions. These structures allow local workplace issues to be connected with wider collective strategies. Internal democracy can involve elections, member meetings, ballots and constitutional procedures, although the precise mechanisms differ between unions and jurisdictions.
Trade union representation can cover both collective and individual matters. Collectively, unions negotiate pay, hours, staffing arrangements and workplace policies. Individually, union representatives may support members facing disciplinary action, grievances, redundancy or disputes concerning contracts. Union officials can also provide advice about legal rights and assist members in pursuing formal procedures. Workplace representatives often possess practical knowledge about local conditions and can communicate information between employees and management.
This representative role can be particularly important where employees feel unable to raise concerns individually. However, union representation depends on membership, resources, recognition by employers and the legal environment. A union cannot necessarily represent every worker in an organisation or compel an employer to negotiate unless applicable law or agreements establish such obligations.
Trade unions are distinct from professional associations, employee networks and political parties, although their activities can overlap. A professional association may focus primarily on occupational standards, professional development or status rather than collective bargaining. An employee network may provide community and support without possessing collective bargaining authority. A political party seeks representation within governmental institutions, whereas a trade union primarily organises around workers and employment interests, although unions can campaign on public policy and may have political affiliations. Trade unions are also distinct from employers' associations, which represent employers rather than employees. These distinctions matter because different organisations possess different legal powers, membership bases and institutional purposes.
Union membership and influence vary according to industry, occupation, employer size, employment status and broader economic conditions. Union density refers to the proportion of workers who are union members, while collective bargaining coverage refers to the proportion whose employment is covered by collective agreements. These measures are related but not identical. A country can have relatively high bargaining coverage even where union membership is lower if agreements have wider institutional reach.
Union influence can be affected by the growth of temporary work, subcontracting, platform work, remote employment and fragmented workplaces because these arrangements can make collective organisation more difficult. Unions have responded in different ways, including organising previously underrepresented workers, using digital communication and negotiating across occupational or sectoral boundaries.
Trade unions remain important institutions within employment relations because they provide collective representation, bargaining capacity and organised worker voice. Their functions can include negotiating employment conditions, supporting individual members, promoting health and safety, influencing labour policy and organising industrial action where legally permitted. Their precise role depends on law, membership, employer recognition, economic conditions and internal organisation. Understanding trade unions therefore requires more than defining them as organisations that negotiate wages. They are institutions of collective action that connect individual employment relationships with wider systems of representation, workplace governance and labour rights. Their historical forms continue to change as employment structures and labour markets evolve.
