The aim of the study was to explore the determinants of well-being and subjective happiness of high school students. The article presents the perception of happiness and the determinants of psychological well-being among high school students. The study was conducted on a sample of 60 high school students in Białystok, aged 16 to 18, using the Ryff’s Psychological Wellbeing Scale and a custom questionnaire to measure subjective happiness. The study employed both quantitative and qualitative methods. The results indicate that youth well-being is influenced by elements such as positive emotions, a sense of security and stability, social relationships, achieving goals and successes, as well as faith and spirituality. Considering the timeline, half of the respondents evaluated that current events have the greatest impact on their happiness. The largest group among the respondents – a total of 39% – rated themselves as less happy than others. The article also discusses the theoretical frameworks of well-being and happiness, including Seligman’s PERMA model and Ryff’s model of psychological well-being.