This study investigated marriage patterns among religious and ethnic groups in Ghorveh district using the characteristics assimilation and norms-cultural hypotheses in explaining difference in marriage patterns. The data source for this study is the 2008 survey conducted among married women aged 15-49 years in rural and urban areas of the district using a structured questionnaire. The results showed that the age of marriage and free mate selection has increased while the proportion of consanguineous marriage has decreased slightly across time for marriage cohorts among religious and ethnic groups. Nevertheless, the results indicated that significant differences exists in marriage patterns among religious and ethnic groups as Kurds and Sunni women have had higher proportions of early marriage, arranged marriage and consanguineous marriage as compared with their counterparts. Furthermore, multivariate analysis revealed that although by controlling for socio-economic characteristics, the religious and ethnic differences in marriage patterns did not disappear and remained significant in the models, these differences decreased significantly. In brief, the results of this study support the characteristics assimilation hypothesis.