Abstract: Tehran as a metropolitan area and as an economic, social and political area has multiple relationships with its surrounding villages and towns at national and regional levels. Functional changes in the rural areas under the influence of Tehran are among important changes that have occurred in the years after the Islamic revolution in Iran. Accordingly, people living in the villages located at the South West of Tehran began to migrate to Tehran during the last thirty years as a result of changing the political system of the country, the lack of suitable planning, the rage of an eight years war between Iraq and Iran and the lack of resources in most parts of the country, especially in rural areas. Consequently, the villages in the South West of Tehran have undergone radical functional changes. This study examines the functional changes of the rural settlements over 1978-2014. To this end, a descriptive-analytical research design was used. The sample under study consisted of 374 heads of households in the sample villages selected using cluster sampling. The results indicated that villages in the Southwest of Tehran during the revolution years were involved mostly in primary functions such as agriculture, animal husbandry and horticulture while the industry and services in rural areas were at the lowest level. However, the changes made in socioeconomic structure of the whole country plus the developments made in the last few decades have not been aligned with the environmental capabilities. The presence of industries, factories and workshops in agricultural lands surrounding villages, low prices of agricultural lands and the expansion of communication networks have extended various functions including industrial and service functions.