A Math Committee comprised of administrators and teachers in one Ohio school district designed and implemented a standards-based Math Improvement Project (MIP) in three K--4 schools to improve math teaching and learning. The purpose of this dissertation study was to determine the perceptions of K--4 math teachers about the strengths and challenges of the project and recommend action steps for improving it. The MIP included various action research phases that resulted in teachers utilizing constructivist-based teaching methods to enhance students' understanding of mathematics. The qualitative study included collecting and analyzing data from five focus group interviews with nine teachers. The findings revealed a number of strengths of the MIP, including greater student engagement, enjoyment, and interest in mathematics; consistent expectations in teaching approaches and curriculum; learning activities that accommodated students' differences; and a high level of support for math reform. The math teachers identified challenges with the MIP in the following areas: the multiple problem-solving approaches; the students' lack of basic skills in reading, writing, and math; instructional planning and teaching time; assessment of constructivist learning; teachers' beliefs and attitudes; and parental concerns. The findings of this study indicate that the school district in this study successfully implemented components of math reform as envisioned by the National Council of Teachers of Mathematics (NCTM) yet the math teachers experienced impediments to successful math reform in the district. These findings suggest that a continuous math improvement cycle, including ongoing evaluations and modifications, is necessary to sustain math reform efforts. In addition, change is required at all levels of the educational system to ensure that students receive a high-quality math education from knowledgeable teachers who are committed to continual professional growth. A number of recommendations for practice and for future research are also addressed.