Background: Collaboration between humanitarian organisations and commercial as well as humanitarian logistics service providers has become of utmost importance when outsourcing logistics activities. Selection criteria for choosing suitable logistics service providers areessential for the success of outsourcing collaboration and disaster operations. Yet, the selection of logistics service providers and the influencing factors for the development of outsourcing collaboration have been neglected by existing literature. Thus, there is a need to generate knowledge about the correlation between collaborative outsourcing and humanitarian logistics. As the UN system is the most relevant humanitarian system for responding to disasters, this case was chosen to provide the study context. Purpose: The purpose of this thesis is to examine the outsourcing collaboration between humanitarian organisations and commercial as well as humanitarian logistics service providersin each of the disaster cycle phases, namely preparedness, response, and recovery. In particular, the selection criteria for collaboration with suitable logistics service providers when outsourcing logistics services within the context of the UN system are investigated. Method: This qualitative research employs an inductive single case study approach based on the context of the UN system. Data was collected and analysed through triangulating multiple data sources including semi-structured interviews, company reports and websites. Data from the different sources was compared and analysed by using a grounded analysis approach.  Conclusion: The study showed that the influence of the factors for outsourcing collaboration are closely connected to the humanitarian needs. This correlation affects the selection criteria for commercial and humanitarian logistics service providers and underlines the need to apply selection criteria for collaboration throughout the disaster cycle. The study further showed that the way of initiating collaboration substantially differs between the types of logistics service provider as it has an impact on the selection of logistics service providers.