Persistent challenging behaviors in early childhood can interfere and disrupt children's engagement in social and academic activities within their homes, schools, and communities (Brauner & Stephens, 2006; Division for Early Childhood [DEC], 2017). To address this concern, DEC recommends that early childhood practitioners use functional behavior assessments (FBAs) to understand what children communicate via challenging behaviors (DEC Recommended Practice [RP] INS9; DEC, 2014; Dunlap & Fox, 2011; Wood et al., 2013). Trial-based functional analysis (TBFA) is a type of FBA that is highly applicable in early childhood settings and thus, can be used by trained early childhood practitioners to determine the function(s) of young children's challenging behaviors (Bloom et al., 2013; Rispoli et al., 2015; Ruiz & Kubina, 2017). The purpose of this article is to describe how practitioners can use TBFAs in early childhood settings to identify the function(s) of challenging behaviors. The article first provides a description of TBFA and procedures to conduct one. Then, it provides a discussion of how to record, graph, and interpret TBFA data. The implementation procedures of each TBFA step are also summarized. Finally, the article addresses how to use key principles of early childhood assessment when conducting a TBFA.