Background <p>Internet addiction (IA) and poor sleep quality are increasingly recognized as behavioral risk factors that may influence adolescents’ overall and oral health. Adolescence represents a critical period for establishing lifelong oral hygiene behaviors, and gingival inflammation is highly prevalent in this age group. This study aimed to evaluate the association between IA, sleep quality, and clinical periodontal parameters among adolescents.</p> Methods <p>This cross-sectional study included 100 systemically healthy adolescents (aged 12–18 years). The sample consisted of both male (47%) and female (53%) participants, predominantly of Turkish ethnicity based on native language, representing middle socioeconomic backgrounds. Data on internet use patterns and sleep quality were collected using the Young Internet Addiction Test (IAT) and the Pittsburgh Sleep Quality Index (PSQI), respectively. Clinical periodontal parameters, including Gingival Index (GI), Plaque Index (PI), Probing Pocket Depth (PPD), and Bleeding on Probing (BoP), were measured by a calibrated examiner.</p> Results <p>Adolescents with poor sleep quality exhibited significantly higher GI and PI scores (<i>p</i> = 0.025 and <i>p</i> = 0.024, respectively). Additionally, the mean IAT score was significantly higher in adolescents with poor sleep quality (<i>p</i> = 0.032). A high frequency of internet use (&gt; 28&#xa0;h/week) was more prevalent in this group (<i>p</i> = 0.020).</p> Conclusions <p>The findings suggest that poor sleep quality and IA may be associated with poorer periodontal health in adolescents. These results emphasize the importance of considering behavioral factors such as digital media exposure and sleep patterns in the clinical assessment and prevention of periodontal diseases during adolescence. However, due to the cross-sectional design of the study, no causal inference can be made. Future longitudinal studies are needed to validate these associations and improve clinical relevance.</p>