Whereas (technical) standards often affect society as a whole, they are mostly developed by men. In the context of the United Nations’ Sustainable Development Goal 5 (gender equality), this article motivates research on the gender gap in standardization, focusing in a first step on the under-representation of women in science, technology, engineering, mathematics and leadership positions as one possible cause. A novel data set of more than 8000 organizations that develop formal standards and 28,000 affiliated experts (10.5% female) confirms that women are descriptively under-represented. A logistic regression shows that organizations’ size, industry, and geographical location are significant factors that are associated with representation by female standardizers. Standard-development for construction, mechanical and electrical engineering is especially male-dominated, while the east of Germany shows more female representation than the west. The presented empirical evidence of female under-representation suggests a need for standard-setting organizations to expand their focus from considering gender in standards documents to actively promoting female participation in their committees. It further adds to the debate on stakeholder representation in standardization and its legitimacy as a co-regulative system in the EU.