A neighbourhood association (also neighborhood association, community association, or residents' association) is a voluntary organization of residents within a geographically defined area who work together to address local issues, advocate on planning and development matters, and foster community cohesion. Neighbourhood associations exist worldwide, though their legal status, organizational structure, and degree of integration into municipal governance vary significantly by country. They are generally distinguished from homeowner associations (HOAs) by their voluntary membership, absence of coercive legal authority over property, and focus on civic advocacy rather than private property regulation.

Research suggests that neighbourhood associations serve as "schools of democracy" in which residents are socialized into political participation and civic engagement. They strengthen links between residents and policymakers, mobilize communities around local concerns, and contribute to the development of social capital. However, scholars and policymakers have also raised concerns about the demographic representativeness of these organizations, particularly in the context of housing supply debates, where associations have been criticized for amplifying the preferences of older, wealthier homeowners at the expense of renters, younger residents, and racialized communities.

The term neighbourhood association is sometimes used interchangeably with homeowner association (HOA), but the two are fundamentally different types of organization.

Neighbourhood associations are voluntary civic bodies. Membership is open to any resident of the defined area (typically including both homeowners and renters), dues are nominal or nonexistent, and the organization has no legal authority to enforce rules on private property. Their influence is exercised through advocacy, persuasion, and participation in public planning processes. In the United States, neighborhood associations may be incorporated as 501(c)(4) nonprofit organizations and enjoy tax-exempt status.

HOAs, by contrast, are typically established by real estate developers and made mandatory through Covenants, Conditions, and Restrictions (CC&Rs) registered on property titles. Membership is automatic upon property purchase and cannot be declined. HOAs levy compulsory assessments, enforce architectural standards, and in many U.S. states possess the legal power to place liens on properties or initiate foreclosure proceedings for non-compliance.

Neighbourhood associations are more commonly found in older, established neighbourhoods that predate HOA-style development, while HOAs are generally created at the time a subdivision is constructed and sold. In some cases, both types of organization may exist within overlapping geographic boundaries.

In the United States, the rules governing the formation and recognition of neighbourhood associations are sometimes regulated at the city or state level. Some American neighbourhood associations are incorporated and recognized by the Internal Revenue Service as 501(c)(4) nonprofit organizations. Neighbourhood councils, a related but distinct type of entity, are governmental structures whose officers are generally elected and which may encompass multiple neighbourhood associations.

American neighbourhood associations typically focus on general advocacy, community events, neighbourhood safety, beautification, and liaison with municipal government. They reinforce community standards through education, peer pressure, and informal social norms rather than through legally binding rules.