This dissertation examines the transformative potential of reflective practice in student assessment and feedback, while also developing tools to gain a nuanced understanding of teacher feedback dispositions and practices. It outlines the development and refinement of three novel tools: the Reflective Classroom Assessment Protocol (ReCAP), the Feedback Benefits and Costs Questionnaire (F-BaCQ), and the Feedback Practices Questionnaire (F-PraQ). Across three interconnected phases, it delves into the multifaceted challenges of feedback-giving and assessment, particularly in contexts where traditional evaluation methods may fall short. The first phase centers on a high school engineering and design teacher on his journey to develop the means to assess student reflections effectively. Rather than prescribing a standardized rubric or grading scheme, the study focuses on uncovering the teacher's tacit knowledge and helping him articulate the learning goals embedded in his instructional design. This led to the creation of ReCAP, an intervention designed to encourage teachers to engage in reflective practice during assessment events. The mixed-methods single-case study showed how ReCAP facilitated notable changes in the teacher's assessment, feedback-giving, and instructional practices, suggesting its potential as a tool for on-the-job professional development. The second phase of the dissertation focuses on the creation and validation of F-BaCQ. This instrument measures teachers' beliefs about the benefits and costs of providing feedback, offering valuable insights into their underlying dispositions and motivations when giving written feedback. The third phase introduces F-PraQ, a complementary tool to F-BaCQ, designed to assess the specific feedback practices teachers report using in their classrooms. Together, F-BaCQ and F-PraQ provide a comprehensive framework for understanding and supporting teachers' feedback approaches, paving the way for more tailored and impactful professional development. The findings from this dissertation underscore the critical role of reflective practice in enhancing feedback quality and suggest that integrating tools like ReCAP, F-BaCQ, and F-PraQ into teacher training and development could lead to more effective teaching and learning outcomes. [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.]