<p>Research in this article refers to the influencing factors during Strategic IoT architecture decisions in small and medium-sized enterprises. Our results reveal the importance of each factor and its influence on other factors. A selection of influencing factors - mainly from literature - is examined for their significance and relations using Interpretive Structural Modeling. The data for the Interpretive Structural Modeling comes from an interview study with high-quality experts from the German-speaking area. Based on the results, a decision environment for practical decision-makers is built up from the influencing factors found. Subsequently, we provide a tactic to manage the decision-making process via a guide for practitioners. The outcome of our research can help SME practitioners control influencing factors on strategic decisions about the IoT architecture to improve the decision outcome. The authors are unaware of any literature source that provides an approach to handling the influencing factors of strategic IoT architecture decisions in small and medium-sized enterprises.</p>