Autism spectrum disorder (ASD) is a neurodevelopmental condition affecting approximately 3 out of every 100 children. Individuals diagnosed with ASD often experience delays in language and communication, impediments in the development of social behavior, and engage in restrictive or repetitive behavior. Evidence-based behavioral interventions have attained a degree of success in supporting the acquisition of life skills that individuals with the diagnosis often fail to acquire spontaneously. Early diagnosis and intervention is critical to maximize intervention gains. In the current chapter, we discuss the general landscape of ASD diagnosis and intervention with an emphasis on emerging behavioral and biological markers with the potential to support early diagnosis of ASD and intervention, including genetic, neuropsychological, behavioral, and intervention-induced neuroplasticity biomarkers.