The authors explore the influence of instructional technologies on teachers' subject-matter knowledge as well as how this knowledge is mediated by context, experience, and beliefs about teaching, mathematics, and technology. This study examined how four pre-service middle grades mathematics teachers' (PSTs) beliefs about teaching, mathematics, and technology influenced their subject matter knowledge specific to the teaching profession (i.e, specialized content knowledge [SCK]). Embedded-unit single case study analysis revealed that PSTs' different beliefs about teaching, mathematics, and technology indicated various impacts of the use of dynamic geometry software on their SCK. PSTs who viewed teaching mathematics with technology as an effective pedagogical decision to support students' understanding and self-discovery of their subject matter knowledge demonstrated more dynamic SCK with dynamic geometry software. The authors discuss interconnections between PSTs' beliefs and knowledge and share implications for technology-enhanced teacher education of middle grades mathematics teachers.