Problematic smartphone use (PSU) and problematic social media use (PSMU) have become major behavioural issues, especially concerning their association with loneliness. An online cross-sectional survey was conducted with 785 Italian adults (82.00% female, Mage = 33.80 years), who completed validated measures of loneliness, fear of missing out (FoMO), social media-related escapism, PSMU, and PSU. The hypothesised model showed excellent fit indices. Loneliness was positively associated with both FoMO (β = 0.849) and escapism (β = 0.528). Moreover, FoMO and escapism were significantly associated with both PSMU (β = 0.622 and β = 0.457, respectively) and PSU (β = 0.604 and β = 0.435, respectively). Importantly, the indirect effects were significant, whereas the direct paths from loneliness to both PSU and PSMU were non-significant, a pattern consistent with a possible full mediation. Indirect effects through FoMO and escapism were significant for both outcomes. Time spent on social media was a strong predictor of PSU and PSMU, while gender and age were not. Findings highlight FoMO and escapism as important psychological factors-associating loneliness with harmful technology use. These processes work both separately and together, providing possible targets for interventions to mitigate PSU and PSMU. The results improve theoretical models of technology overuse and stress the need to address emotional and cognitive vulnerabilities in prevention strategies.