["Journal of Child Psychology and Psychiatry, EarlyView. ", "\n\nBackground\nAltered social cognition in autism may be influenced by difficulties in domain‐general functions, such as selective attention. Here, we manipulated the requirement for selective attention during a visual perspective taking (VPT) task and used neurophysiological indices to delineate underlying mechanisms.\n\n\nMethods\n43 autistic and 38 neurotypical children and youth completed a VPT paradigm. Participants' and an avatar's perspectives were either congruent or incongruent, manipulating the demand for selective attention to inhibit irrelevant information processing. Group differences in dependence on the attended perspective and congruency were examined for behavioral performance, event‐related potentials (ERPs), and in a subsample, stimulus‐evoked pupil response (SEPR).\n\n\nResults\nAutistic participants showed reduced accuracy when rating an avatar's perspective and pronounced perspective‐related differences in a late‐frontal slow wave (LFSW). Incongruency elicited stronger effects on behavioral performance and LFSW in autistic relative to neurotypical participants. Additionally, generally larger and more sustained SEPR was observed for autistic participants, reflecting an alteration that was dissociable from LFSW differences. Across groups, SEPR and ERP measures explained both distinct and partially overlapping variance in response slowing.\n\n\nConclusions\nFindings support attenuated VPT abilities and difficulties to deploy selective attention in autistic youth. Altered fronto‐cortical activation patterns in the LFSW likely reflect an increased top‐down involvement in VPT. Concurrently, pupil responses indicate an increased cognitive effort when reporting visual perspectives. Findings emphasize a co‐characterization of social cognition difficulties by social and domain‐general functions in autism.\n\n"]