Instructional scaffolding is a powerful tool that many teachers utilize to meet the challenge of individualizing instruction for diverse learners. The concept of instructional scaffolding is complex (Meyer, 1993), in that teachers have to determine what, how much, and what kind of help to give to students in a moment’s notice (Rodgers, 2004/05). Gaining expertise with scaffolding can take years, which leads us to worry about the effectiveness of novice teachers. A scarcity of research examining how to support a teacher’s development of instructional decisions such as scaffolding is reported (Anders, Hoffman, & Duffy, 2000). The ability to make scaffolding decisions requires teachers to be cognitively flexible, drawing from multiple domains of understanding to meet the individual needs of a group of students. However, little is known about which domains and understandings teachers draw on during scaffolding events or the rationales underlying this decision-making process. This naturalistic study examined the decision-making processes of a novice elementary ESOL teacher as she scaffolded instruction for her third-grade students. As she videotaped what she considered to be a successful scaffolding event each week, we unpacked the event together using the lens of Cognitive Flexibility Theory (CFT). The guiding questions were: (1) How can the decision-making processes underlying a novice ESOL teacher’s instructional scaffolding be described? (2) How can the lens of Cognitive Flexibility Theory inform a novice ESOL teacher’s scaffolding decisions? Data sources included interviews, field notes, and reflections of the sessions. Constant comparative analysis (Glaser & Strauss, 1967; Miles & Huberman, 1994) was used to analyze data. Rigor was demonstrated by establishing credibility, transferability, dependability, and confirmability (Lincoln and Guba). A grounded theory model of a kaleidoscope was created to describe the novice ESOL teacher’s decision-making processes during scaffolding events. The participant’s decisions were influenced by a variety of pedagogical and contextual domains while also being impacted by her views on scaffolding, on assessment, and on the connection between theory and practice. The participant’s conceptions of scaffolding became more complex and her confidence and sense of agency became stronger as a result of mentoring underpinned by CFT.