© 2018 Ballespí et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Recent advances suggest that impairment in social cognition (SC) may play a role in the development of social anxiety (SA). However, very few studies have analyzed whether SA fosters poorer social-cognitive development as it leads to social avoidance. This study aimed to analyze whether retrospectively assessed behavioral inhibition (BI) (i.e., an early form of SA) in childhood is associated with a deficit in social cognition operationalized as impairment of mentalizing (MZ) in adolescence. A sample of 256 adolescents (range: 12–18 years; mean age: 14.7 years; SD = 1.7) from general population were assessed for MZ capacities and retrospective BI through self-report and interview measures. Results comparing three groups of adolescents with different levels of childhood BI (low, moderate or high) and controlling for concurrent SA and depression reveal that the higher the level of BI, the lower the level of MZ. These results were consistent for almost all mentalization measures, including when both extreme (i.e., high vs. low BI) and non-extreme (i.e., high vs. moderate BI) were compared in both self-report and interview measures and in both dimensions of MZ (i.e., MZ referred to others’ and to own mental states). These findings support that childhood forms of SA are associated to deficit in SC in adolescence. A possible bidirectional relationship between SA and SC, and the role that it may play in the pathway to clinical SA are discussed.