Introduction: The widespread adoption of technology has highlighted problematic behaviors such as smartphone and internet misuse, particularly among university students, with significant implications for psychological and social well-being. Purpose: This study investigates the relationships among smartphone misuse, internet misuse, loneliness, emotion regulation difficulties, and aggression, focusing on the potential mediating roles of loneliness and emotion regulation. Method: A sample of 104 university students (aged 18-45, M = 26.12, SD = 6.84), reporting no psychiatric or neurological diagnoses, voluntarily participated. Data were collected using the Smartphone Addiction Scale-Short Version, Young's Internet Addiction Test-Short Form, Buss-Perry Aggression Questionnaire, UCLA Loneliness Scale, and Difficulties in Emotion Regulation Scale. Analyses were conducted using SPSS 30.0, employing correlation, multiple linear regression, and mediation analyses. Results: The findings indicated significant positive correlations among all variables (r = .18-.65, p < .001), with smartphone misuse exhibiting a strong association with aggression (r = .43, p < .001) and loneliness (r = .59, p < .001). Regression analysis indicated that smartphone misuse significantly predicted aggression (β = .47, t(99) = 3.98, p < .001), explaining 25.2% of the variance (R² = .252, F(4,99) = 8.35, p < .001), while internet misuse, loneliness, and emotion regulation were not significant predictors. Mediation analyses showed that neither loneliness (β = −.03, p = .236) nor emotion regulation (β = .04, p = .222) mediated the smartphone misuse-aggression relationship. Internet misuse directly predicted aggression (β = .24, p = .014), but mediation effects were not significant. Conclusions: Smartphone misuse may increase aggression, which is potentially driven by stress from constant connectivity and nomophobia, in line with the framework of the General Aggression Model for activating aggressive cognitions. Our findings suggest that device characteristics may play a more prominent role in understanding aggression than the type of content mediated by the device.