An IoT eco-system includes IoT network components, network services and network participants such asorganizations, consumers, governments, and businesses. Due to its diversity and scale, trustworthiness is a criticalconcern to be considered during architectural design and the operational phase of these eco-systems. To do this,security, privacy, reliability, resilience and safety must be assured. However, existing solutions partially address theserequirements using centralized approaches that come with challenges such as a single point of failure, scalability,and dependence on a third party. In this context, Distributed Ledger Technology (DLT) and Smart Contracts, due toits intrinsic properties of transparency, immutability, and underlying secure-by-design architecture allows distributed,decentralized, automated workflows which can be incorporated to automate the management of the next generationIoT networks. In this paper, we propose a framework for IoT eco-systems providing seamless integration betweenIoT and DLT to create a decentralized trusted architecture which ensures trustworthiness of IoT eco-systems atdesign time and a trust reputation model based on the architecture to protect it during the run-time. Furthermore, wehave presented the initial steps towards the implementation of this framework.