Effective transition planning is of paramount importance in maximizing post school outcomes for students with disabilities. The purpose of this study is to examine data from the National Longitudinal Transition Study--2 regarding the transition planning for students with mental retardation. In addition, for comparison purposes, data on transition planning for emotional/behavioral disorder (E/BD) and learning disabilities (LD) students were also examined. Findings from this study indicate that (a) nearly 60% of students with mental retardation (MR) had their transition planning begun by age 14; (b) students with MR were less involved in their transition planning (about 10% did not participate at all), less likely to provide input (less than half of those participating), and more likely to report no progress towards transition goals than the other two groups of students; (c) general educators' involvement in MR students' transition planning was minimal though related service personnel was more involved; (d) a small percentage of students with MR had postsecondary education as a transition goal, while more of them had sheltered and supported employment as a transition goal; (e) students with MR were more likely to have other agency personnel involved in transition planning. (Contains 5 tables.)