In light of the expansion of student-centered instructional approaches in mathematics education and a brightening spotlight on virtual teacher supports, I look to Inquiry-Oriented Instruction (IOI) and explore how instructors reflect on and plan for their implementation of IOI in online professional development. I focus specifically on two teachers' comments on their implementation of IOI materials covering Abstract Algebra topics in online work groups developed to support teachers in implementing IOI. I analyze both reflection and enactment through the components of IOI characterized through a framework model called the Instructional Triangle. Analysis of the teachers' reflections, viewed through their participation in the roles of sense maker, inquirer, and builder, revealed interesting differences in the teachers' approaches to IOI. I detail these two teachers' approaches to IOI and ultimately shed light on the intricacies of IOI and online professional development. Such findings support the growing bodies of research centered around IOI and corresponding professional development. Advisors/Committee Members: Johnson, Estrella (committeechair), Norton, Anderson Hassell (committee member), Wawro, Megan (committee member).