Recent research has shown that emphasizing the importance of effort for learning mathematics can have positive effects on students' achievement, engagement and sense of competence (Dweck, 2010; Middleton & Jansen, 2011; National Mathematics Advisory Panel, 2008). In order for teachers to focus on the importance of effort, they need to believe that success in mathematics is attributable to effort (i.e., growth mind-set) and not a result of some inherent ability (i.e., fixed mind-set). Achievement goal theory provides a framework for examining teachers' instructional practices with regards to an emphasis on effort versus ability. Mastery-oriented instructional practices tend to emphasize effort, improvement and challenges while performance-oriented teaching practices focus on using competitive instructional methods and highlighting ability differences in students (Anderman et al., 2001). Although teacher education programs may focus on the importance of effort versus ability and promote the use of mastery-oriented instructional practices in mathematics, beginning elementary teachers may struggle to use mastery-oriented teaching due to factors such as their own experiences as K-12 students, experiences during student teaching, and aspects of their school and district contexts. The purpose of this study was to explore the views and teaching practices of a small group (n = 10) of elementary teachers who had recently graduated from the same university teacher preparation program and were teaching upper-elementary mathematics. Using data from teacher surveys, student surveys, teacher interviews, and classroom observations, I explored the following research questions: (1) When teaching mathematics, do early-career upper elementary teachers who graduated from a specific teacher preparation program use instructional practices that are mostly mastery-oriented, mostly performance-oriented, or a more balanced combination of both? (2) What factors seem to be associated with whether early-career upper elementary teachers use mastery-oriented and/or performance-oriented instructional practices in mathematics? (3) How do early-career upper elementary teachers describe and communicate their views about success in mathematics? How do their students view success in mathematics? The results showed that the 10 teachers who participated in the study reported and were perceived to be using more mastery-oriented than performance-oriented instructional strategies in mathematics. In order to examine the factors that seemed to be associated with teachers' uses of different practices and teachers' views about success in mathematics, I used an in-depth case study approach informed by a situated perspective on learning to teach mathematics (Borko et al., 2000; Peressini et al., 2004). In the first case study, I found that Diane and Luke's focus on mastery-oriented teaching practices in mathematics was in large part due to the strong degree of alignment they experienced among their second mathematics methods course, their cooperating teachers' practices, and their own personal visions of teaching. In the second case study, I found that Andrea and Kelsey's active participation in certain communities of practice seemed to have a strong influence on their learning and use of mastery-oriented teaching practices in mathematics. With regards to teachers' views about success in mathematics, I found that Diane, Luke, and Andrea all seemed to communicate views consistent with a growth mind-set while Kelsey seemed to have elements of both a growth and fixed mind-set. Based on limited survey evidence, there was evidence that students in all four classrooms might have had beliefs about success in mathematics that were consistent with both fixed and growth mind-sets. I conclude by discussing implications for teacher education and future research. [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://www.proquest.com/en-US/products/dissertations/individuals.shtml.]