Earthquake is one of the most important natural hazards that causes great damage to human societies every year and sometimes lead to major crises and disasters. Due to its geological location and locating on the seismic belt, Iran has several active faults and is one of the most seismic countries in the world, and has suffered many losses due to earthquakes during different periods. Meanwhile, rural settlements are the most vulnerable areas to earthquakes as a result of their special conditions such as high population concentration in some high-risk areas of the country, low level of technology and lack of access to durable materials, personalization of housing and non-compliance with safety principles in construction, non-standard infrastructure, poor location and lack of access to facilities and services and low level of training and skills. Thus, having sufficient knowledge of the possible vulnerability of rural settlements to plan and avoid damage, can be very effective in the crisis management process. The research aims to assess the vulnerability of rural settlements in Iran to seismic risk. The study population includes all rural settlements in Iran. The data used in this paper has been collected from the Statistics Centre of Iran in 2011. In this research, after reviewing the literature, 12 variables in the form of 3 main criteria (population, type of materials, age of houses) have been used to assess vulnerability. First, seismic risk zoning (low, medium, high) was done based on previous studies, available data and experts' opinions. Then to assess the vulnerability of rural settlements, a fuzzy inference system has been used by creating a database of knowledge-based rules and defining 594 rules in Matlab software environment, and the final output is displayed with Arc GIS software. The results show that about 45% of the population and rural houses are located in areas with high seismic risk. Furthermore, based on the vulnerability to earthquakes, Iran's rural settlements are located in three levels with low, medium and high vulnerabilities, most of which, in other words, about 70% of Iran's rural settlements are located in the category with high vulnerability.