This study examined children's perceived barriers to attending school-based anxiety treatment. One hundred and twenty-two anxious youth ("mean" age = 11.03 years; 51.6% female; 46.7% non-white) were randomized to receive either a modular cognitive behavioral anxiety treatment or usual care. The frequencies of 13 child-reported perceived barriers were examined following randomization and during one of the first three treatment sessions. Correlates of perceived barriers were also examined using a multi-informant assessment including: (1) child/family demographics, (2) child clinical characteristics, and (3) parental/family factors. Results indicated that 87.7% of children reported at least one perceived barrier to attending treatment. The most common barriers were worries about missing classroom work (45.3%) and the stigma associated with receiving mental health services (37.7%). Several factors were correlated with greater perceived barriers including minority racial/ethnic background, low parental education, higher child anxiety, and higher teacher-reported child externalizing behavior in the classroom. A multiple regression model showed that the strongest association was between teacher-rated externalizing behavior and children's perceived barriers. Although school-based treatment removes logistical problems, children's perceived barriers are still common. Assessing and reducing these perceived barriers, particularly among racial minority families and families with parents who did not attend college, may be beneficial. [This article was published in "School Mental Health" (EJ1229487).]