Professional Development for Transformational Technology Integration: An Experimental Study of In-Service Teachers' Self-Perceptions of Technological Pedagogical and Content Knowledge Elena M. Tachau Drexel University Chairperson: Brian K. Smith, Ph.D. The rapid advancement of technology tasks K-12 schools with providing professional development for technology integration. This study sought to address the effectiveness of a TPACK-aligned professional development model in preparing in-service teachers to use technology in ways that transform teaching and learning. Through a single-subject, experimental mixed methods design, this study investigated the relationship between a TPACK-aligned professional development intervention and teacher self-assessment of the following TPACK framework constructs: technological knowledge (TK), technological content knowledge (TCK), technological pedagogical knowledge (TPK), and technological, pedagogical and content knowledge (TPACK) in a rural, K-12 public school district. The following question guided this research: How does a TPACK-aligned professional development model influence teacher self-assessment of TPACK? The findings of this study contribute to existing literature on the design of professional development for technology integration in technology-rich learning environments and address a gap in the literature on TPACK-aligned, in-service teacher professional development for transformational technology integration. [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.]