Background/Objectives: The co-occurrence of Attention-deficit/hyperactivity Disorder (ADHD) and Autism Spectrum Disorder (ASD) is very common and worsens adaptive functioning. This systematic review evaluates both pharmacological and non-pharmacological interventions in this underserved population. Methods: Registered on PROSPERO (CRD42024526157), a systematic search was conducted on PubMed, Embase, and Web of Science until 5 April 2025. The review includes (a) pilot studies and RCTs, (b)…