This study evaluated attention, sensory processing, and social responsiveness and the relationship between these constructs among autistic and neurotypical adults. Participants included 24 autistic adults (17-30 years) and 24 neurotypical peers who completed the Test of Everyday Attention, Adolescent/Adult Sensory Profile (AASP), and the Social Responsiveness Scale--2. Autistic individuals showed greater attention, sensory processing, and social responsiveness challenges compared to neurotypical peers. Using mediation models, we showed that the relationship between attention and social responsiveness was mediated by sensory processing, specifically the low registration and sensation-seeking AASP quadrants. The relationship between attention, sensory processing, and social responsiveness suggests that adults with greater attention issues may have greater sensory and social challenges. Specifically, having poor attention may lead to poor sensory processing skills which compound poor social responsiveness. Understanding the relationships between these domains is critical for developing effective interventions and support for autistic adults.