Youth with intellectual disabilities have been found to experience poor postschool outcomes compared to youth with other disabilities and youth in the general population (Newman, Wagner, Cameto, & Knokey, 2009). To improve postschool outcomes, several best practices are recommended by researchers and professionals in the field of transition either specifically for youth with intellectual disabilities or all youth with disabilities. A handful of studies have examined the extent to which best practices are implemented and some nonexperimental studies have found that best practices are predictive of postschool outcomes. However, no study has yet examined whether the combination of several best practices is predictive of outcomes in multiple domains for youth with intellectual disabilities or provided a comprehensive examination of whether individual, family, and school characteristics make a difference in whether youth with intellectual disabilities experience best practices. The present study analyzed data from the National Longitudinal Transition Study-2 to examine the extent of use of best practices and factors that affect best practice use, and to identify whether best practices are predictive of postschool outcomes after controlling for other factors for youth with intellectual disabilities. In descriptive and comparative analyses, variation was found in the proportion of youth who had received each of the best practices with almost all youth reported to have received transition planning and less than half of youth reported to have experienced interagency involvement, yet there was no discernible pattern in the characteristics of youth that was associated with an increased likelihood of receiving each best practice. In predictive logistic regression analyses, the combination of five best practices was found to significantly predict the outcomes of employment, postsecondary education, and enjoyment of life after controlling for youth, family, and school characteristics. In these analyses, parent expectations for employment and postsecondary education were some of the strongest predictors of postschool success. Although this study had several limitations, these findings suggest that best practices may be predictive of postschool success and highlight the importance of having high expectations for all youth. These findings must be replicated in future longitudinal research studies.