Over the past twenty years, significant advances have been made in addressing intrinsic and extrinsic barriers to technology integration that has led to an increased use of technology-supported teaching and learning in the classroom. However, a key challenge remains in the design and implementation of professional development programmes, for both pre-service and in-service teachers, which can increase the impact of technology-enhanced classroom practices. This thesis presents three studies that examined second level teachers’ technology integration in their classroom practices. The first and second case studies discusses the practices of two cohorts of teachers (n=15). The first cohort were awarded a set of tablet devices for a whole year group, the second cohort were provided tablets by the research team for one academic term. The final study, which built upon the findings in case studies one and two discusses the design and implementation of an undergraduate module for second level pre-service science teachers (n=10), with no prior teaching experience, to extend their technological pedagogical knowledge. These studies present data collected from teacher’s lesson plans, interviews, and independent classroom observations. The Technological Pedagogical Content Knowledge Framework (TPACK), proposed by Koehler & Mishra (2006), was used as an operational framework to discuss teacher’s classroom practices. The results of this thesis highlight that even though the barriers to technology integration have been significantly reduced, and in some cases eliminated, teachers continue to struggle to integrate technology in their pedagogical practices. While school-based professional development was shown to increase in-service teachers’ use of technology-enhanced strategies, the teachers’ felt they required significantly more support, both to design and implement changes in their classroom practices. The pre-service teachers believed the exposure to new technologies and tools enhanced their confidence and attitudes to integrating technology in their pedagogical approaches. However, observations from a micro-teaching observation with this cohort illustrated that these pre-service teachers had good levels of technology literacy but generally low TPACK levels. This research has focussed on the teachers’ approaches to technology-enhanced classroom practices, however further research needs to be conducted to examine the impact on student learning. In addition, it highlights the need for extended studies on the design and implementation of different models for professional learning programmes that can impact on the technology-enhanced classroom practices of both pre- and in-service teachers.