Findings from a meta-analysis of studies investigating the use of five different assistive technology devices (switch interfaces, powered mobility, computers, augmentative communication, weighted/pressure vests) with young children with disabilities are reported. One hundred and nine studies including 1,342 infants, toddlers, and preschoolers were the focus of analysis. Results showed that the use of all the assistive technology devices except weighted and pressure vests were related to improvements in the child outcomes regardless of type of child disability or severity of child intellectual delay. The importance of the use of evidence-based training methods for promoting practitioners' and parents' use of assistive technology is described. The following are appended: (1) Background Characteristics of the Study Participants; and (2) Research Designs, Types of Assistive Technology, Outcome Measures, and Cohen's d Effect Sizes for the Relationships between Use of the Assistive Technology Devices and the Child Outcomes.