This document presents 20 guiding principles developed by the ET 2020 Working Group on Vocational Education and Training (WG on VET) in 2014-2015. These principles were developed during a series of meetings, in-depth country focus workshops and webinars. Representatives of the EU Member States, EFTA countries, and candidate countries as well as EU Social partner and VET provider organisations, Cedefop and the European Training Foundation (ETF) participated in the working group, which was chaired by the Commission. Cedefop and external consultants have contributed to the working group through... background documents and research activities. The key purpose of the WG on VET is to respond to the objectives of ET 2020, Rethinking Education, and the Bruges Communiqué as well as the Riga conclusions of June 2015; notably the call to governments, social partners and VET providers to promote work-based learning in all its forms, with special attention to apprenticeships, and to make related policies more effective and more targeted to the labour market needs. The rationale is that promoting work-based learning, including apprenticeships, can help young people make a smoother transition from school to work, improve their employability and hence, contribute to reducing youth unemployment. The guidance principles respond to four policy challenges that are important to address in the promotion of apprenticeships and other forms of work-based learning: national governance and social partners' involvement; support for companies, in particular SMEs, offering apprenticeships; attractiveness of apprenticeships and improved career guidance; and quality assurance in work-based learning.