The purpose of the paper is to solve the problem of managing information systems development projects in situations where the organization forms a joint team with consultants. The joint project team consists of members of the client and consulting organizations. Therefore, good cooperation is needed during the implementation of the project in order for the project to be successful. The solution to the problem lies in the formation of a model of inter-organizational coordination between the client and the consultant. The elements of the model are related to agency problems and project uncertainty. In the case of agency problems, we analyzed the alignment of goals and the level of trust. With project uncertainty, we analyzed demand uncertainty and technical uncertainty. The scientific contribution of the work refers to the creation of a model of inter-organizational coordination that can be effectively managed in order to increase the success of the project. The contribution also refers to new scientific facts and findings related to coordination theory and agency theory. The practical contribution of the work refers to the applicability of the created model and the provision of information to managers of the client organization for better management of information systems development projects in the joint team of the client and the consultant.