Abstract: This paper reports on a three-year qualitative research study examining the professional development program, “Making Connections” offered to teachers in grades 5-9 in a large Midwestern urban, high-need school district. The goal of this program was to assist teachers in understanding the concept of curriculum integration and increase their ability to teach an integrated STEM lesson plan in traditional math, science, and special education classrooms. Using a multidisciplinary integration approach, the engineering design process served as the central theme for math and science lessons. An interdisciplinary integration approach was used to integrate technology and Universal Design for Learning principles for differentiating instruction. Results of the study indicated that teachers developed a good understanding of the concept of curriculum integration and were excited about the potential of this teaching method for making math and science more meaningful and engaging for students. This paper reports on the theoretical framework of the professional development model, research methods, and conclusions.