Technology has become a vital part of our professional and personal lives. Today we cannot imagine living without many technological tools such as computers. For the last two decades technology has become inseparable from several areas, such as science. However, it has not been fully integrated into the field of education. The integration of technology in teaching and learning is still challenging even though there has been a historical growth of Internet access and available technology tools in schools (U.S. Department of Education, National Center for Education Statistics, 2006). Most teachers have not incorporated technology into their teaching for various reasons such as lack of knowledge of educational technology tools and having unfavorable beliefs about the effectiveness of technology on student learning. In this study, three beginning science teachers who have achieved successful technology integration were followed to investigate how their beliefs, knowledge, and identity contribute to their uses of technology in their classroom instruction. Extensive classroom observations and interviews were conducted. The findings demonstrate that the participating teachers are all intrinsically motivated to use technology in their teaching and this motivation allows them to enjoy using technology in their instruction and keeps them engaged in technology use. These teachers use a variety of technology tools in their instruction while also allowing students to use them, and they posit a belief set in favor of technology. The major findings of the study are displayed in a model which indicates that teachers' use of technology in classroom instruction was constructed jointly by their technology, pedagogy, and content knowledge; identity; beliefs; and the resources that are available to them and that the internalization of the technology use comes from reflection. The study has implications for teachers, teacher educators, and school administrators for successful technology integration into science classrooms. [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.