<p>The purpose of this thesis was to investigate the nature of knowledge transfer among key organisations in the New Zealand (NZ) research and development (R&D) sector. From these findings, practical implications for Information and Communication Technology (ICT) support were drawn. Knowledge-intensive R&D activities have seldom been investigated from a social network perspective. As Allen et al. (2007) point out there is a lack of research addressing the issue of knowledge transfer in inter-organisational social networks, specifically in the R&D sector. By employing social network analysis (SNA), this study addressed this gap and analysed and identified inter-organisational knowledge transfer structures and processes among organisations by focussing on three cases. Key themes related to SNA included the identification of the network topology, informal key roles of organisations by their levels of interactivity in the networks and their types of relationships for transferring knowledge. The concepts underlying social network analysis played a significant role in informing this research. Using a mixed method approach of case research and social network analysis, this thesis comprises an in-depth investigation into the nature of knowledge transfer among key R&D organisations in the NZ environmental sector. The mixed methods approach employed followed three consecutive steps for each of the three cases. First, a qualitative phase was conducted. Data were collected from workshop/seminar participants. This helped to achieve a deeper understanding of the field under study, and the results were used to develop an online survey instrument for the second quantitative phase. In this quantitative phase the online survey was distributed to employees of various R&D organisations. In total, 168 participants took part in this survey. Besides addressing SNA concepts, additional key themes covered by this survey were types of knowledge transferred, media used and preferred media characteristics as well as knowledge services for learning. In a final qualitative phase the workshop/seminar participants were asked follow-up questions in relation to key survey results with the aim of confirmation and explanation. This research aimed to address practical and theoretical issues alike. From a practical perspective, this research provides important background information on how to increase collaboration among R&D organisations in New Zealand. R&D key players, such as Crown Research Institutes, private research organisations, universities, government departments, and industry organisations, need to collaborate more in order to increase commercialisation of research knowledge, reduce costs (e.g. reuse knowledge) and drive innovation. From a theoretical perspective, this thesis adds knowledge to the application and further development of SNA concepts, such as tie strength, centrality and network structure, in an inter-organisational knowledge transfer context. Key findings were the definition of intermediate ties and their importance for knowledge transfer in inter-organisational social networks, recommendations of suitable centrality measures for knowledge networks and the identification of small-world networks in the R&D sector. Finally, implications for ICT support could be drawn. These implications may help increase inter-organisational collaboration. Possible ICT support was categorised into three levels that appeared useful in this study's knowledge transfer context: the individual level, the group level and the inter-organisational level.</p>