Background: Tinnitus can significantly impact a patient's quality of life. As no evidence-based curative treatments exist, therapies such as cognitive behavioral therapy, tinnitus retraining therapy, acceptance and commitment therapy, and mindfulness-based interventions aim to minimize tinnitus severity and have been shown effective. Since traditional delivery can be costly and time-consuming and often has limited accessibility, therapies might also be provided via eHealth. This study investigates the change in tinnitus severity measured by the Tinnitus Functional Index (TFI) score after participation in an online self-paced tinnitus ("Still Tinnitus") course. The secondary aim was to identify predictors for the clinically relevant improvement after participation in this course. Methods: This retrospective record study included patients from Still Tinnitus course between March 2023 and July 2024. Patients were recruited via the Still Tinnitus website. Differences in the TFI scores from baseline and after completing the fifth (last) module of the course were calculated to investigate the change in tinnitus over time. Multivariate logistic analyses were performed to identify the possible predictors for the clinically relevant improvement after completion of the Still Tinnitus course. Results: In total, 122 patients were included in the study. The analysis revealed a clinically relevant reduction in the TFI score of 27.2 points. Multiple regression analyses showed that the "duration of the tinnitus" (OR 5.0; 95%CI: 1.537-16.240; p = 0.007) and "female sex" (OR 1.9; 95%CI 0.111-7.637; p = 0.030) are predictors for a clinically relevant improvement. Conclusions: In a convenience sample of tinnitus patients, the Still Tinnitus course may contribute to a clinically relevant reduction in tinnitus severity. A shorter duration of tinnitus and female sex were identified as significant predictors.