This thesis set out to research the problem of loneliness among adolescents in the high school context. For a long time, loneliness had mainly been recognized as a problem among elderly. Only in the last few years, people have been starting to realize that this is a concerning problem among adolescents too. In order to get a better grip on what loneliness is, and what the role is of the high school context, extensive research was done to answer the main research question: Following the current situation in Delft, which steps should be taken next in the high school context to better deal with loneliness among adolescents? Four sub questions were formulated in order to define the challenges and opportunities for the design phase. Answers to the sub questions were found through various research activities, like literature research, expert interviews and contextmapping sessions. Analysis of the data led to seven main insights. Following these insights, it was explored what a better way was to look at the problem. Currently, loneliness among adolescents is framed as problematic, because it can progress into chronic loneliness with severe consequences. Existing initiatives that aim to solve this problem often help adolescents to step out of social isolation or help them improve their social skills. Besides that, loneliness is also framed as something that does not happen to young people, which makes adolescents struggle with identifying with the word, or they feel ashamed to admit when they do feel lonely. In order to take steps towards a more preventative and holistic approach, the problem was reframed: a problem of ignorance, by not treating the feeling as something we all experience and that teaches us about our underlying human needs. Following this new frame and additional exploration, the design statement was formulated: we want to show high school students how feelings like loneliness are indicators of underlying, fundamental human needs by letting them collectively reflect on these needs and thei relation to emotions, while also making them aware of the universality of those needs. A creative design process followed. Potential design directions were explored through brainstorming and organizing a focus group. Validation of the concept was done through a user test and by interviewing stakeholders. The concept was detailed further and the Under-Needs toolkit was introduced. The Under-Needs toolkit provides the tools for the high school context to educate students on their emotions and underlying needs. While it does not directly tackle loneliness, it aims to teach students how to reflect on feelings like loneliness and trace them back to underlying needs. This will help them to make better sense of feelings like loneliness because they get taught how to see them in the bigger picture.