The Washington Assessment of Risk and Needs of Students (WARNS) is a brief self-report measure designed for schools, courts, and youth service providers to identify student behaviors and contexts related to school truancy. Empirical support for WARNS item invariance between ethnic groups is lacking. This study examined differential item functioning (DIF) to ensure that items on the WARNS function similarly across groups, especially for groups where truancy rates are highest. The item response theory graded response model was used to examine DIF between Caucasian, African American, and Latinx students. DIF was identified in six items across WARNS domains. The DIF amount and magnitude likely will not influence decisions based on total scores. Implications for practice and suggestions for an ecological framework to explain the DIF results are discussed.