Postsecondary transition plans and services include domains such as independent living, postsecondary employment, and postsecondary education and have positive lifelong benefits for students with intellectual disabilities (ID). School psychologists have much to contribute to the transition process, but previous studies have indicated they often have limited involvement in this domain. A survey was conducted to assess school psychologists' current knowledge, attitudes, and behaviors regarding transition services for students with ID. Respondents included 282 practicing school psychologists from the United States and Canada. Regression results indicated that attitude, knowledge, and previous experience with the ID population were significant predictors of performance of transition-related professional behavior. Responses to open-ended questions supported the quantitative survey results and highlighted the importance of instruction (direct, informal, and experiential) in school psychologist delivery of transition services. Given this, recommendations to increase school psychologist knowledge of and positive attitudes toward transition planning and students with intellectual disabilities and their families are discussed.