This article explores how Danish school girls affectively engage with and relate to STEM subjects, and what draws the girls to STEM subjects and pushes them away, respectively. We draw on Ahmed's work to shed light on the 'sticky' affects that become attached to STEM subjects as well as student subjects in constituting these as affectively (un)attractive for girls. We explore the discourses on STEM subjects that circulate amongst the students before considering the affects that these discourses generate in and amongst the students, and which roles these affective reactions play in how the girls engage with and relate to STEM. Our analysis evolves around three affective tensions in the data and shows that positive affects are felt by and attached to students with STEM interests and skills, and that students negotiate different kinds of (dis-)comfort when relating to their engagement with STEM in the present and in the future.