Background Excessive media use can affect diet of adolescents, but relevant data in Saudi Arabia are lacking. The present study aimed to explore the association between media use, dietary intake, and diet quality among adolescents. Methods This cross-sectional study included data of 631 adolescents (ages 11–18 years) who were randomly recruited from 16 schools located in two main cities in the Western region of Saudi Arabia (Madinah and Jeddah). Envelopes including a questionnaire were sent home to collect sociodemographic data. Students then completed the short-form food frequency questionnaire to assess diet quality. Data on media use, anthropometrics, and 24-h dietary recalls were also collected. Results A high proportion of adolescents (86.2%) exceeded media use recommendations of ≤2 h per day. Significantly higher proportions of younger adolescents, males, and non-Saudis reported media use within the recommendation compared to their peers. Media use predicted lower diet quality score (B = −0.67 [95% CI: −1.09 to −0.28]) and lower intake of calcium, zinc, vitamin D, and vitamin C (B = −104 [95% CI: −203 to −5.24], B = −2.13 [95% CI: −4.15 to −0.11], B = −23.5 [95% CI: −41.3 to −5.65], B = −24.0 [95% CI: −45.1 to −2.96], respectively). Conclusion Interventions to limit media use are urgently needed for adolescents in Saudi Arabia to improve diet quality and overall nutritional health. Impact Excessive media use can affect diet of adolescents, but relevant data are lacking in Saudi Arabia. The majority of adolescents exceed the recommendations for media use. Media use was negatively associated with diet quality and intake of calcium, zinc, vitamin D, and vitamin C. This study will inform public health entities and policy makers to draw evidence-based, culturally tailored recommendations and develop nutrition interventions to enhance diet quality and nutritional status of adolescents. Findings of this study highlight the urgency to develop intervention programs and policies that aim to limit media use among adolescents.