Federal and state policies concerning disability issues are often made based on advocacy efforts by individuals with disabilities and their allies. Providing self-advocacy and leadership training to youth with disabilities has been widely regarded as critically important to promote legislation and policies that support these individuals. This study evaluated the effects of the youth leadership summer training on the self-advocacy abilities of high school students with disabilities. A nonequivalent group design was used. The sample included 68 high school juniors and seniors aged 16 to 22, with 34 in the experimental group and 34 in the control group. The Texas Statewide Youth Leadership Forum Pre/Post Questionnaire was used to measure the participants’ self-advocacy abilities a week prior to the training and immediately following the training. Results indicated that the training improved the self-advocacy abilities of the participants, individuals with developmental disabilities gained significantly more than the other disability groups, and gender did not interact with treatment to affect the self-advocacy abilities of these participants. Implications to policy and practices are discussed.