Gaps in gender data and the lack of trend data make it difficult to monitor progress for women and girls. Unless gender is mainstreamed into national statistical strategies and prioritized in data collection, gender data scarcity and gaps will persist. Investment in national statistical capacity is central to improving the coverage, quality and timeliness of data for monitoring gender equality and the SDGs. But beyond this, making sure that data represent the lived reality of women and girls in all their diversity by addressing deep-seated biases in concepts, definitions, classifications and methodologies, is essential to making women and girls visible.