The cerebellum has been involved in social abilities and autism. Given that the cerebellum is connected to the cortex via the cerebello‐thalamo‐cortical loop, the connectivity between the cerebellum and cortical regions involved in social interactions, that is, the right temporo‐parietal junction (rTPJ) has been studied in individuals with autism, who suffer from prototypical deficits in social abilities. However, existing studies with small samples of categorical, case–control comparisons have yielded inconsistent results due to the inherent heterogeneity of autism, suggesting that investigating how clinical dimensions are related to cerebellar–rTPJ functional connectivity might be more relevant. Therefore, our objective was to study the functional connectivity between the cerebellum and rTPJ, focusing on its association with social abilities from a dimensional perspective in a transdiagnostic sample. We analyzed structural magnetic resonance imaging (MRI) and functional MRI (fMRI) scans obtained during naturalistic films watching from a large transdiagnostic dataset, the Healthy Brain Network (HBN), and examined the association between cerebellum–rTPJ functional connectivity and social abilities measured with the social responsiveness scale (SRS). We conducted univariate seed‐to‐voxel analysis, multivariate canonical correlation analysis (CCA), and predictive support vector regression (SVR). We included 1404 subjects in the structural analysis (age: 10.516 ± 3.034, range: 5.822–21.820, 506 females) and 414 subjects in the functional analysis (age: 11.260 ± 3.318 years, range: 6.020–21.820, 161 females). Our CCA model revealed a significant association between cerebellum–rTPJ functional connectivity, full‐scale IQ (FSIQ) and SRS scores. However, this effect was primarily driven by FSIQ as suggested by SVR and univariate seed‐to‐voxel analysis. We also demonstrated the specificity of the rTPJ and the influence of structural anatomy in this association. Our results suggest that there is a complex relationship between cerebellum–rTPJ connectivity, social performance and IQ. This relationship is specific to the cerebellum–rTPJ connectivity, and is largely related to structural anatomy in these two regions.

Practitioner Points : We analyzed cerebellum–right temporoparietal junction (rTPJ) connectivity in a pediatric transdiagnostic sample. We found a complex relationship between cerebellum and rTPJ connectivity, social performance and IQ. Cerebellum and rTPJ functional connectivity is related to structural anatomy in these two regions.