This document summarizes Victoria Tsoukala's presentation on open science at the European Commission (EC). It discusses: 1) The EC's role as a policy maker, funder, and capacity builder in promoting open science. 2) Why open science is important for advancing science, the economy, and society by increasing access, transparency, and impact of research. 3) The EC's open science policies and requirements in Horizon 2020 and Horizon Europe, including open access to publications and research data with exceptions when necessary. 4) Key initiatives to advance open science like the European Open Science Cloud, open research publishing platforms, and responsible data management.