The purpose of this study was to determine how middle school math teachers implemented formative assessment in their mathematics classrooms, including whether and how they used technology to do so. There were three key questions that guided this study: 1) How do middle school teachers plan for and collect data for formative assessment during a mathematics lesson? 2) In what ways do teachers use evidence gained from formative assessment to change their instruction, if at all? and, 3) To what degree do middle school mathematics teachers use technology when engaging in formative assessment during a mathematics lesson? I used a qualitative research design in this study, which included document analysis, observations, and teacher interviews, to collect data from five middle school mathematics teachers. The research revealed three significant findings: 1) Formative assessment activities in these middle school mathematics lessons fell into one of three categories; Purposefully Planned for, Not Planned for but Used, and Missed Opportunities. 2) When teachers did include formative assessments in their Acquisition Lesson Plans, it was rare that the plans also included the exact interventions they would use if the data showed that some or all of the students held some misunderstanding. While teachers did frequently add new math problems to their instruction or modify the mode of instruction, those changes often came the next day in a multi-day lesson as opposed to in the exact moment that the formative assessment activity occurred. 3) Although teachers embedded formative assessments into lessons that were delivered through the use of technology and a learning management system, Schoology, they did not use technology solely for the purpose of formative assessment. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://bibliotheek.ehb.be:2222/en-US/products/dissertations/individuals.shtml.]