<p>Sensor-based Internet of things are integral to numerous applications like environmental monitoring, healthcare, smart homes, and industrial automation. These applications enable real-time monitoring and automation, reducing human intervention and enhancing efficiency of the deployed system. In such autonomous applications, decision-making plays a pivotal and significant role in making intelligent decisions with minimal human interaction. Trustworthy decision-making is fundamental for ensuring the integrity and reliability of these automated systems. This research work focuses on the evolution of trustworthiness for Sensor-based IoT (SIoT) and investigated the impact of various attack types on trust levels. In this paper, a novel framework for trustworthy decision protocol has been designed and implemented using SIoT. The trustworthy SIoT networks are explored with the focus on the behaviour of sensor nodes, group leaders and central authority. The effects of various attacks have been evaluated for trustworthy relations. These include bad-mouthing, good-mouthing, and on–off attacks which affect the trust relationships among nodes. Simulations have been carried out to analyze trustworthiness along with the impact of attacks on trust levels. The results provide the insights with the resiliency of the proposed trust-based decision-making protocol in SIoT systems with reference to existing protocols.</p>