Recently emerging intervention studies for toddlers with autism spectrum disorders (ASD) were reviewed through a systematic assessment of intervention outcomes, research rigor, and intervention features. The review includes published peer-reviewed experimental studies of toddlers with high risk for or diagnosis of ASD in which the majority of interventions occurred before age 36 months. Of 20 identified research studies, 6 were group comparison studies, all of which showed small to large magnitudes of effect when a uniform metric was applied. Fourteen were single-case design (SCD) studies, all of which reported effects on a variety of outcomes. When grouped by area of intervention focus (communication, general development, family well-being, imitation, joint attention, and play), commonly identified needs within focus areas were for replication, common measures, and authentic practices. A majority of studies in most focus areas showed strong to acceptable levels of research rigor, though this is an area of ongoing need. (Contains 3 tables.)