Particle physics research has a long tradition of making scientific advancement through large-scale collaborative efforts. With the unprecedented scale of CERN’s Large Hadron Collider came a real need for extensive efforts in communication, education, and outreach. The International Particle Physics Outreach Group (IPPOG) was formed in 1997 as a European initiative (then EPPOG) to become an international player with the development of the International Particle Physics Masterclass programme. IPPOG became a scientific collaboration in 2016 with 30 countries, six experiments, CERN and two associate members participating. IPPOG brings new discoveries to young people and to the public at large and has evolved as a strategic pillar of particle physics.