Koksal, BurakTopkaya, Nursel2026-02-032026-02-0320251046-13101936-4733https://doi.org/10.1007/s12144-025-07905-whttps://hdl.handle.net/20.500.12428/34904The aim of this study is to develop a self-help intervention based on acceptance and commitment therapy; to examine the effect of the self-help intervention on the depression, anxiety, stress, and psychological flexibility levels of university students; and to examine their experiences. In this study, we used a mixed explanatory basic design. In the quantitative part of the study, we used a 2 (experimental and control group) x 3 (pretest-posttest and follow-up test) experimental design. The participants consisted of 47 university students. The experimental group received a 7-week guided self-help intervention based on acceptance and commitment therapy, whereas the control group received no intervention. Participants completed a Personal Information Form, Depression Anxiety and Stress Scales-42, and Acceptance and Action Questionnaire-II. We conducted semi structured interviews to examine the experiences of participants in the experimental group. We analyzed the data using an independent samples t test, repeated measures ANOVA, one-way ANCOVA, and content analysis. According to the study's results, we found guided acceptance and commitment therapy-based self-help intervention decreased students' depression, anxiety, and stress levels and increased their psychological flexibility levels. The qualitative findings of the study revealed four general concepts: difficulties experienced while implementing the intervention program, prominent parts of the intervention program, benefits of the intervention program, and components of the intervention program. We discussed self-help experiences in light of the relevant academic literature.eninfo:eu-repo/semantics/openAccessSelf-helpAcceptance and commitment therapyCollege studentsDepressionAnxietyStressPsychological flexibilityT & uuml;rkiyeMixed method researchArticle4411111261114310.1007/s12144-025-07905-wQ1WOS:0014913863000012-s2.0-105005555409Q1