Purpose: The purposes of this study were first to identify and describe transition to adulthood pathways of youth with Serious Emotional Disturbance (SED) in regards to the timing and order of transition to adulthood task completion (e.g. completing education, gaining employment, living independently, marrying/close personal relationship, and becoming a parent). It then evaluated the relationship between transition pathway and use of social services (e.g. SNAP, TANF, Medicaid, etc.), and contact with the justice system (e.g. arrest, incarceration, probation). Methods: This study is a secondary data analysis using self-report data from the National Longitudinal Transition Study 2 (NLTS2). A latent class analysis of responses from 950 youth with SED ages 13 to 26 years and their caregivers was conducted to determine how youth with SED experienced transition task completion. Once pathways were identified, social service use and justice system contact were examined by transition pathway for group differences. Results: Two pathways through the transition to adulthood for youth with SED were identified. Approximately half of youth (53%, Class 2) in this study experienced early transition task completion, including school (most by age 19), and a steady rate of gaining employment and independent living. These youth were more likely to be from households above the poverty level, Caucasian, and to report higher social assertiveness skills. Youth in the second identified pathway (47%, Class 1) reported transition task completion as a gradual process. They were more likely to still be engaged in school or other educational programing well into their 20s and less likely to be employed, living independently, or parenting (Class 2). They were also more likely to be from households below the poverty level, less likely to be Caucasian, and reported lower social assertiveness skills. Due to limitations in the data, social service use and criminal justice system contact were not able to be fully examined based on transition pathway. However, consistent with the literature, youth with SED reported a high rate of social service use (TANF 23%, food stamps/SNAP 33%, social security income 39%, Medicaid/Medicare 51%) and justice system contact (arrested 49%, jailed 27%, probation/parole 27%). Conclusions: Findings allowed for the identification of a proportion of youth with SED (47%, Class 1) that achieved transition tasks, markers of independence into adulthood, more gradually than their peers. Based on the characteristics of this subset of youth who were at risk of delayed transition, it is important to focus interventions on minority, low income youth with SED and lower social skills. A key component of intervention should be focusing efforts when youth were still of school age, as findings indicate youth are already on their transition trajectory by age 18. More research is needed to follow youth with SED into adulthood and determine the impact of alternative transition pathways. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://www.proquest.com/en-US/products/dissertations/individuals.shtml.]