Although LGBTQ youth are at risk for peer rejection, substance abuse, mental health disorders, and dropping out of school, research shows that most mental health training programs do not include a course on working with this population (Carroll & Gilroy,2001; Matthews, 2005; McCabe & Rubinson, 2008;Sherry, Whilde, & Patton, 2005; Murphy, Rawlings, & Howe, 2002; Savage, Prout, & Chard, 2004; Walker & Prince, 2010). This study examined the effectiveness of a professional development workshop on the self-perceived competency of school mental health professionals in working with LGBTQ youth. Participants were school mental health professionals with varying experience from public school districts in Massachusetts. The author hypothesized that participants would rate themselves higher on measures of self-perceived competency (Sexual Orientation Counselor Competency Scale (SOCCS)) and score higher on measures of knowledge immediately after participating in the workshop and at a follow-up period. Overall, the median SOCCS scores and post-test knowledge scores were significantly higher immediately following the workshop and at follow-up compared to the pre-test measures. Additional analyses indicated that both profession (e.g., Guidance Counselor vs. School Psychologist) and confidence prior to the workshop significantly predicted the median different from pre-test to post-test on the SOCCS. [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.]