The Helmholtz Initiative for Accelerator Research & Development (ARD) was established to strengthen development in accelerator physics and technology and to ensure international competitiveness. In this framework, accelerator scientists push the limits of today’s technology in a research network of six Helmholtz centers (Deutsches Elektronen-Synchrotron (DESY) in Hamburg and Zeuthen, Helmholtz Zentrum Dresden-Rossendorf (HZDR), Forschungszentrum Jülich (FZJ), Helmholtz Zentrum for Heavy Ion Research GSI in Darmstadt, Karlsruhe Insitute for Technology (KIT), and Helmholtz Zentrum Berlin for Materials and Energy (HZB) ), two Helmholtz institutes, eleven universities, two Max-Planck institutes, and the Max-Born institute. The third ARD topical workshop on “ps - fs Electron and Photon Beams” will focus on three fundamental areas of current research in the field of short pulse particle accelerators, namely research related to synchronization and seeding, ultra-fast pulse diagnostics, and photon radiation and interaction. The workshop aims to bring to together scientists from universities and Helmholtz centers that are involved in the subtopic 3 (ST3) “ps – fs Electron and Photon Beams” of the ARD program. It shall serve to further strengthen collaborative projects at and between the different accelerator facilities. The workshop shall also serve to educate young researchers and students participating in projects and experiments within ST3.