This thesis describes how Innovation Management Consultants (IMCs) can promote changes in R&D/marketing relationships. The research was motivated by the scarce number of studies about the impact of IMCs on organisational relationships in general, and particularly on R&D and marketing relationships. This thesis contributes to knowledge in four strands of literature: technology management, organisational change, management consulting and conflict studies. Firstly, its main contribution is to technology management literature. Empirical evidence indicates that IMCs can modify the relationship between R&D and marketing functions, even though they are not hired explicitly for that purpose. Nonetheless, the main impact on the relationship is perceived at the personal level and it is dependent on the format of the intervention process. Additionally, the changes in the R&D/marketing relationship and its continuity seem to be conditional upon contextual factors such as specific company and consultant characteristics, as well as the nature of the consultant-client relationship. Secondly, this study has added to scholarly knowledge in organisational change by providing empirical evidence that IMCs advocate for the same dynamics used by Organisational Development (OD) consultants. The results highlight the importance of a facilitative-participative approach and organisational learning to generate change. The results suggest that certain OD theories such as sociotechnical systems theories and Lewin’s model can be used to explain the effect of IMCs on intra-organisational relationships. Thirdly, this research also augments knowledge about IMCs in management consulting literature because it provides evidence about the activities conducted by IMCs and their unexpected effects within client organisations. This addresses a gap identified in the literature, since the contributions of this type of Management Consultant (MC) have not been significantly investigated and the focus of previous studies has been on expected results. Finally, this research contributes to the area of conflict studies, particularly to the intersection between R&D/marketing integration and conflict, since it provides certain evidence about some IMCs’ mediation techniques that can be used to diminish conflict between different areas within an organisation. The research followed an inductive approach to understanding the changes that IMCs can promote in R&D/marketing relationships in large firms. The research is based on empirical evidence gathered through twelve case studies, feedback interviews and a small-scale survey. A framework describing the possible changes that IMCs can promote in the R&D/Marketing relationship was then built from grounded, within-case, and cross-case analysis. Lastly, in order to verify the observations obtained during the case studies, as well as the pertinence of the proposed framework, a set of eight feedback interviews with company participants and IMCs were carried out, as well as a small-scale survey. The results of these verification activities indicate that the proposed framework is reasonably complete and its elements are coherent.