This dissertation is comprised of three studies investigating the teaching practices of a cohort of pre-service teachers in a university-based teacher education program. The first manuscript characterizes the improvements of a cohort of eight pre-service secondary mathematics teachers (PSMTs) over the course of an academic year in the year prior to their student teaching. The purpose of this study was to document changes in PSMTs' teaching quality over a two-semester mathematics pedagogy course through the use of Mathematics Scan (M-Scan), a multidimensional instructional observational tool based on the NCTM's vision of quality mathematics instruction. The second paper focuses on two of the PSMTs from the aforementioned cohort of pre-service teachers to highlight their different growth trajectories and improvements in instructional practices. The third paper seeks to answer this question by following one of the PSMTs into her student teaching. It characterizes her teaching practices throughout her semester of student teaching at a local public high school using M-Scan to score a subset of lessons during that time, feedback comments given to her after her lessons, and her own reflections on her teaching practices. Collectively, these studies suggest that university-based teacher preparation programs can help pre-service mathematics teachers improve in developing standards-based instructional practices. [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.]