The current study aimed to identify the social support and its relationship to decision making among unmarried girls in the South Al Batinah Governorate at Sultanate of Oman. Correlative descriptive design was used. The study sample consists of (830) respondents who were selected randomly. Social Support instrument was developed by current researcher, and Scale of marital adjustment "Arabic version" was used. The results showed that both level of social support associated with the marriage decision and the level of marital adjustment were high. There was significant correlation between the social support associated with the marriage decision and the level of marital adjustment among sample. According to variables, the results showed that there was significant difference in the level of social support associated with the marriage decision due to age when marriage decision taken in favor of who their ages (21-25) and above 26 years. According to current age variable, the results showed that there was significant difference in both the level of social support associated with the marriage decision and the level of marital adjustment in favor of who their ages (30 years or less).