Learning from activism, usually informal and unrecognised, is an important component of industrial relations and a major learning source for individuals, organisations and society. Young workers who lack support from existing employee organisations may create their own. Based on studies of social movement organisations in highly diverse industrial relations systems (Austria, Spain’s Basque Region, Slovakia), this chapter presents a framework for analysing and comparing novel social movement organisations’ position within industrial relations systems. Each was founded because its national system did not adequately address challenges. Activism enables young people employed in workplaces unfavourable to learning, or unemployed, to compensate for what better workplaces offer. Youth-led social movement organisations generate important knowledge and practical skills, challenging established organisations, including trade unions, and renewing industrial relations structures.