This study investigated the impact expectancy beliefs had on third through fifth-grade teachers’ instructional teaching practices. These instructional teaching practices included how teachers used their pedagogical content knowledge, specifically their content knowledge for teaching mathematics and formative assessment, to make scaffolding decisions while supporting students in mathematics intervention. The investigation included the analysis of stratified sampling procedures, expectancy beliefs, observations, and self-reported scaffolding ratings. A multiple case study was conducted to understand how four participants, the teachers in the study, expected students to perform in mathematics intervention along with the participants’ pedagogical content knowledge and the impact those beliefs and knowledge had on scaffolding practices. Scaffolding practices highlighted in this study were the teachers’ use of cognitive activation, mathematical discourse, and handling errors productively. Findings suggested that even though teachers demonstrated having content knowledge for teaching mathematics and effective use of formative assessment the teachers still scaffolded just-in-case students might need it during mathematics intervention. The results also suggested that teachers relied upon their expectancy beliefs of students to make scaffolding decisions more than the teachers relied upon their own pedagogical content knowledge. Additionally, this study found that a scaffolding workshop focused on teacher actions may impact the teachers’ self-reported ratings and in turn the teachers’ scaffolding practices. Discussion of the findings in relation to the current literature and their implications was provided. Continued research was suggested to examine how teachers self-rate their scaffolding practices pre- and post-scaffolding workshops and the impact that may have on teachers’ scaffolding practices. These findings add to the research in the field of mathematics education in equitable teaching practices, mathematics intervention, and scaffolding practices.