Educators consider how new technologies can be used in schools to improve student learning, teachers must adjust how they plan for teaching, instruct during a class period, and assess student knowledge. In the following article, I discuss how use of an online mathematics curriculum affects the teachers' role with respect to planning, instruction, and assessment. I incorporate research from educational studies, the experiences of teaching professionals, and my own classroom practices to help teachers anticipate and analyze how they can adjust their teaching when implementing an online curriculum in a mathematics classroom. The article is written following the submission guidelines for a National Council of Teachers of Mathematics journal.