Using IEA's Trends in International Mathematics and Science Study (TIMSS) 2019 data, this brief explores the relationship between students' gender, their confidence and achievement in mathematics and science, and their aspirations to pursue careers in these fields. We find that more boys than girls at grade 8 want to have a mathematics- or science-related job. Girls and boys who have high confidence in mathematics and science are significantly more likely to want to work in these fields than those with low confidence in mathematics. In addition, we find that boys want to pursue a job involving mathematics as adults significantly more than girls of the same achievement level. This increased likelihood for boys holds across both high- and low-achievement groups. In comparison, there are smaller or no gender differences in the likelihood of pursuing a science-related career depending on achievement levels. The brief concludes with a discussion on the potential implications.