This study provides quantitative evidence on the employment, education, and service receipt outcomes of transition-age youth (ages 14 to 25) who enrolled in the Social Security Administration’s Youth Transition Demonstration (YTD). The findings are based on five projects in which eligible youth were assigned to a treatment group that received YTD services and a control group that did not receive any additional services. In all projects, youth engagement in activities and services was lower following high school, and the YTD interventions increased youth engagement, particularly among post-high school youth compared to youth in high school. The findings point to the challenges that youth with disabilities face after they leave high school and enter a fragmented service environment. The findings also illustrate the important role that interventions that target transition-age youth can play in helping youth become productively engaged, especially following high school.