Introduction: This study aims at examining the direct and indirect mediating role of the intolerance of uncertainty (IU) variable in the relationship between COVID-19-induced OCS and depression in a Turkish adolescent sample. Methods: The sample consists of 427 people (248 females, 179 males) between the ages of 14-18, living in Turkey and selected by convenient sampling method. The data were collected through the COVID-19 Obsessive Compulsive Disorder (OCD) Scale, Depression, Stress and Anxiety Scale (DASS-21) and Intolerance of Uncertainty Index-A for Children (IUI-A-C). Results: The findings show that COVID-19-induced OCS have strong predictive effects on depression symptoms. The findings also revealed that IU directly and indirectly mediates the relationship between COVID-19 OCD and depression symptoms, as well as its negative predictive effect for depression symptoms. Discussion: It can be said that OCS caused by COVID-19 trigger depressive symptoms in adolescents. In addition, it can be thought that IU, with its mediator effect, may play a triggering role in the emergence of COVID-induced OCS. Another research finding is that IU may be an important transdiagnostic construct for depressive symptoms. Limitations: The current study has also some limitations. First, the study was carried out as a cross-sectional study. The fact that the sample group is non-clinical and a clinical group is not included can be considered as second delimitation. Third, the current study just used scales to evaluate the students' self-report. At this point, a different perspective can be developed by taking the opinions of the parents. Conclusions: The results show that COVID-19-induced OCS increase depressive symptoms in Turkish adolescents and IU has a mediating effect in this relationship. In addition, the results provide important data for the treatment of mental symptoms related to the pandemic.