The OECD Future of Education and Skills 2030 report on mathematics curriculum presents first-of-its-kind comparative data on how countries are adapting curricula to meet the demands of the 21st century. The project's unique data illustrate a 25-year evolution of mathematics curricula in various countries, looking at content coverage and the integration of essential 21st-century skills like problem-solving, critical thinking, and data literacy. The findings show how mathematics as a school discipline -- a traditionally "hard-to-change" subject given its foundational and hierarchical nature -- is undergoing transformation to meet societal and technological demands. Using a collaborative "co-creation" approach, the report synthesises inputs from a wide range of stakeholders including policy makers, academic experts, school leaders, teachers, NGOs, social partners and, most importantly, students. This broad, inclusive perspective enriches the report with insights on implementation gaps, students' voice, and promising examples on how to embed future-oriented competencies alongside rigorous content into mathematics curriculum. [This report is produced by the OECD's Future of Education and Skills 2030 (Education 2030) project.]