- Background : Polygamy is defined as a marriage in which a spouse of either gender has more than one mate at the same time. Polygamy is considered a valid form of marriage in many countries and communities around the globe. Aim : The purpose of this study is to examine the psychological symptoms, family function, marital satisfaction, life satisfaction and the degree of agreement with the practice of polygamy among â€˜senior wivesâ€™ â€“ the first wife in the polygamous marriage â€“ and women in monogamous marriages in the West Bank, Palestine. Method : A convenience sample of 309 women, 187 from polygamous and 122 from monogamous families, participated in this study. All women from polygamous families were senior wives. The following instruments were deployed: the McMaster Family Assessment Device (FAD), the ENRICH marital satisfaction questionnaire, the SCL-90 mental health symptoms checklist, the Rosenberg self-esteem (SE) scale, the Diener et al. (1985), a life satisfaction scale, and a basic socio-demographic scale, including the degree of agreement of the practice of polygamy. Results : The findings revealed significant differences between senior wives in polygamous marriages and wives in monogamous marriages with regard to family functioning, marital satisfaction, self-esteem and life satisfaction. Likewise, many of the mental health symptoms were different. Particularly noteworthy were somatization, depression, hostility psychotism and the General Severity Index (a global index of distress). More women in polygamous marriages agreed with the practice of polygamy than their monogamous counterparts. Conclusion : Practitioners and policy makers need to be aware of the consequences of polygamy on first wives and on society as whole.