One essential characteristic of the Action Design Research (ADR) method is researcher-practitioner collaboration (RPC). The purpose of this paper is to present theoretical models for RPC collaboration in ADR projects. The models involve conditions, actions, and consequences concerning RPC challenges. A grounded theory approach was applied to identify the RPC challenges. The challenges were identified in a collaborative ADR project consisting of four researchers and nine organizations from the industry sector. The identified main challenges are: researcher intervention in practitioner contexts, reciprocal shaping between artifacts and design principles emerged from theory and practice, and researcher and practitioner learning. The contribution to practice, which consists of future ADR projects involving collaboration between researchers and practitioners, involves specific actions to be taken.