The Confederación Nacional del Trabajo is a Spanish confederation of anarcho-syndicalist labor unions, which was long affiliated with the International Workers' Association (AIT). When working with the latter group it was also known as CNT-AIT. Historically, the CNT has also been affiliated with the Federación Anarquista Ibérica ; thus, it has also been referred to as the CNT-FAI. Throughout its history, it has played a major role in the Spanish labor movement.

Anarcho-syndicalism is a political philosophy and anarchist school of thought that views revolutionary industrial unionism or syndicalism as a method for workers in capitalist society to gain control of an economy and thus control influence in broader society. The goal of syndicalism is to abolish the wage system, regarding it as wage slavery. Anarcho-syndicalist theory generally focuses on the labour movement. Reflecting the anarchist philosophy from which it draws its primary inspiration, anarcho-syndicalism is centred on the idea that power corrupts and that any hierarchy that cannot be ethically justified must be dismantled.