Sue Thomson was featured as a keynote speaker for the 2021 Network Gender & STEM Conference. She provided a knowledgeable and research-informed presentation on STEM participation, achievement, and beliefs. Given gender differences continue to exist in some areas, she highlighted how females do not enrol in higher mathematics, science or ICT, or move into STEM-based careers to the same extent as males. For example, while the number of people employed as ICT specialists in the EU grew by 36% during the period from 2007 to 2017 (more than 10 times higher than the corresponding increase of 3.2% for total employment), the proportion of women employed in these fields has stagnated. This keynote summary addresses three broad areas that may hold females back from participation in these subjects in school and in entering STEM careers: 1) whether men are better at maths, science, ICT than women, 2) perceived ability – self-confidence and self-efficacy, and 3) cultural beliefs.