People with intellectual disabilities (ID) often engage in problem behaviors, such as verbal or physical aggression, property destruction, or self-injury. These behaviors become a challenge for the families and for professionals. Functional behavioral assessment (FBA) is a method used to identify variables that influence or maintain challenging behaviors (CB) and aid in the development of intervention plans. Two major concerns of FBA are that it is time-consuming and requires specialized professionals to interpret data from the natural or experimental environment. Therefore, indirect FBA methods can be used as an alternative. An instrument with excellent psychometric properties that aims to identify the function of behavior is the Questions About Behavioral Function (QABF). This study presents the adaptation of the QABF in Spain. Data from 300 participants with ID and 328 behavioral problems were obtained. An exploratory factor analysis was conducted to identify the components of the QABF, and the test-retest reliability was assessed to evaluate the stability of the QABF over time. (Contains 3 tables.)