The social difficulties that are a hallmark of autism spectrum disorder (ASD) are thought to arise, at least in part, from atypical attention toward stimuli and their features. To investigate this hypothesis comprehensively, we characterized 700 complex natural scene images with a novel three-layered saliency model that incorporated pixel-level (e.g., contrast), object-level (e.g., shape), and semantic-level attributes (e.g., faces) on 5,551 annotated objects. Compared with matched controls, people with ASD had a stronger image center bias regardless of object distribution, reduced saliency for faces and for locations indicated by social gaze, and yet a general increase in pixel-level saliency at the expense of semantic-level saliency. These results were further corroborated by direct analysis of fixation characteristics and investigation of feature interactions. Our results for the first time quantify atypical visual attention in ASD across multiple levels and categories of objects. •A novel three-layered saliency model with 5,551 annotated natural scene semantic objects•People with ASD who have a stronger image center bias regardless of object distribution•Generally increased pixel-level saliency but decreased semantic-level saliency in ASD•Reduced saliency for faces and locations indicated by social gaze in ASD Wang et al. use a comprehensive saliency model and eye tracking to quantify the relative contributions of each image attribute to visual saliency. People with ASD demonstrate atypical visual attention across multiple levels and categories of objects.