We are pleased to announce the IVth school of Astroparticle Physics, dedicated to Gravitational Waves, to be held during the week of 27 May 2013 on the site of the Observatoire de Haute Provence (France). The school will be focused on multi-messenger astronomy involving gravitational waves. Experts will cover a variety of topics relevant for this challenge of the near future. Besides training young researchers who consider joining this emerging field, the objective of the school is to bring together the various scientific communities, getting them to learn about common interests and building synergies.