It is reported that 30-90% of children with developmental disabilities have various behavior problems such as self-harm, attack, and destructive behavior (Matson, Wilkins, & Macken, 2009). Behavior problems that occur in the individual with developmental disabilities interfere with his or her adaptation in many areas. In this regard, literature shows that “Applied Behavioral Analysis(ABA)” based on learning theory is an evidence-based treatment of behavior problems. Treatment based on ABA is reported to be more effective when a “Functional Assessment” is preceded (McIntosh, Brown, & Borgmeier, 2008). Functions for behavior problems include demand, automatic, attention, tangible, and physical condition (Iwata et al., 1982; Matson & Vollmer, 1995). Researches support the hypotheses that the results of functional assessments are different according to the type of behavior problems (Asmus et al., 2004), environment(이효정 외, 2015), and reporters(van der Ende, Verhulst, & Tiemeier, 2012). Therefore, the purpose of our study is to identify the functions of behavior problems according to the types of behavior problems and reporters. As a measure, we used “Functional Assessment for Challenging/Problem Behaviors(FAPB)”(정경미, 김수연, 정다이, 2017), which was developed and standardized for the purpose of identifying functions of behavior problems.