It is puzzling to note that the ‘sea-change’ in the family size in Oman (from about 9 births in 1988 to 3.3 births per woman in 2008) has occurred in the midst of many paradoxes, which is still remained unnoticed. This study provides a critical review of the recent fertility decline in Oman and its underlying causes. The study is based on data obtained from available national-level surveys, published reports, and the World Population Prospects report. The massive economic and social development, women education and participation in the labor force brought a big change in family formation, reproductive behavior, and lifestyles of women, resulting in a fertility decline in Oman. Delayed age at marriage and spacing birth appeared as the major cause of fertility decline in Oman. The tradition of prolonged duration of breastfeeding also contributes to declining fertility. The Omani government should be aware of the current trends in fertility and its consequences, and adopt the culturally appropriate policy for future population management.