In recent years, logistics emerged as a key function in the humanitarian sector. Data show that humanitarian organizations spend a consistent amount of their budgets for logistics and supply chain-related activities. Although their supply chains present a potential for improvement, humanitarian organizations often lack the internal skills and expertise to improve the efficiency and effectiveness of logistics operations. The existing literature dealing with the improvement of humanitarian logistics mostly focuses on the perspective of humanitarian organizations. This thesis looks at the system from a novel perspective, taking logistics consultants as its primary unit of analysis. The departure point of this research is the idea that consulting projects constitute a mean for solving logistics issues. Given this goal, logistics consultants often struggle with the management and measurement of their service performance. HELP Logistics, a foundation operating in this sector, has been facing this situation, driving the need for a solution. Available literature on logistics consulting provides some frameworks to evaluate the performance of interventions, but to date, there is no study that addresses this issue for the humanitarian space. This research aims to fill this gap, analysing and measuring the impact of consulting services on the logistics performance of humanitarian organizations. To do so, the action research (AR) approach is adopted. This methodology is suitable to investigate and encourage changes within organizations. Four main stages can be distinguished in AR: (i) identification of research questions; (ii) gathering of information to answer the questions; (iii) analysis and interpretation of information; (iv) sharing of results with participants. Findings elaborate on the challenges and best practices in relation to the impact of logistics consulting in the humanitarian sector. The research output is a conceptual framework for impact creation through logistics consulting for humanitarian organizations, supported by a set of relevant key performance indicators (KPIs). These results contribute to the existing scientific knowledge on the issue, while providing tools that can be applied by interested practitioners.