The mental health of school students has been severely impacted by the aftermath of the COVID-19 pandemic. The present study used a mixed methods approach to assess students' mental health and examine their wishes for support to improve their psychological well-being. We further investigated gender and age group differences in the amount of clinically relevant mental health problems and the roles that mental health and gender had on desired support. Between April and May 2022, a total of 616 Austrian students aged between 14 and 20 participated in a cross-sectional online survey (77.4% female; 19.8% male; 2.8% non-binary) assessing wishes for support regarding mental well-being and mental health indicators (depression: PHQ-9; anxiety: GAD-7; insomnia: ISI; stress: PSS-10; eating disorders: SCOFF; alcohol abuse: CAGE). A wish for support was expressed by 46.6% of the students. Qualitative content analysis revealed that the two most important categories of desired support types were "professional help" and "someone to talk to". The group of students with a wish for support in general significantly more often showed clinically relevant depression, anxiety, insomnia, eating disorders, or high stress symptoms. Students that wished for professional help significantly more often exceeded the cut-off for clinically relevant depression, anxiety, and high stress. Those who wished for someone to talk to significantly more often exceeded the cut-off for clinically relevant eating disorders. The results indicate a great need for support for young people's mental health problems and that this need is even more urgent for students.