In this article, the author describes the impact of the Great Science Share for Schools (GSSfS). This annual campaign has already engaged over 100,000 pupils since its start in 2016. With 2019 seeing a record-breaking 63,614 pupils registered across 483 events in 11 countries, the forecast for 2020 is looking positive. Set up by the Science & Engineering Education Research and Innovation Hub (SEERIH) at the University of Manchester in 2016, the campaign will celebrate its fifth birthday in 2020. The values underpinning the GSSfS are that it remains child-focused, inclusive and non-competitive, with a collaborative thread through events taking place on and around the campaign date. Free registration means there is access to all, with no restriction on the size or scale of involvement.