Objective: The aim of this study was to examine the mediating effect of social media use on the relationship between negative emotional state and hopelessness levels of young adults during COVID-19 outbreak. Methods: As a quantitative research method, a relational survey model was used for the research. The participants consisted of 586 young adults aged between 18 and 40 years, of which 250 (42.7%) were male and 336 (57.3%) were female. The mean age of the participants was 28.40 ± 5.73 years. The data were collected via personal information form, Depression-Anxiety-Stress Scale, and Beck Hopelessness Scale (BHS). PROCESS Macro regression analyses were used in the data analysis process. Results: According to the findings, the levels of negative emotional state of the participants were high and their hopelessness levels were moderate. The average daily use of social media is approximately 4 hours. The duration of social media use has a low level of positive correlation with negative mood and hopelessness. The duration of social media use has a partial mediating effect on the relationship between negative mood disorder and hopelessness. Conclusion: Findings show that negative emotional state increases the duration of social media use. The increase in the duration of social media use increases hopelessness levels. Negative emotional state and social media use have been found to be risk factors for hopelessness. The results of the research were discussed within the scope of the literature, and various suggestions were presented.