This study is the first to examine and compare the psychological symptomatology, self-esteem and life satisfaction of women in polygamous and monogamous relationships in Syria. A convenience sample of 276 women was studied, of whom 163 were senior wives in polygamous marriages and 113 were wives in monogamous marriages. Findings revealed that senior wives in polygamous marriages experienced lower self-esteem, less life satisfaction and more mental health symptomatology than women in monogamous marriages. Many of the mental health symptoms were different; noteworthy were elevated somatization, depression, hostility and psychoticism. Implications for mental health practice, policy and further research are discussed.