Purpose: The purposes of this study were to examine the level of social support, health promoting behaviors and depression among unmarried pregnant women and to identify the relationship between social support, health promoting behaviors and depression. Method: A descriptive correlational study was conducted. The participants were 102 unmarried pregnant women receiving shelter services from four facilities in two metropolitan cities. Data was collected using a self-administered questionnaire. Descriptive statistics, ANOVA and Pearson correlation were used for data analysis. Results: The level of social support and health promoting behaviors were relatively lower and the level of depression was relatively higher than those of married pregnant women. The participants received especially low social support from their unmarried partner. There was a positive relationship between social support and health promoting behaviors. Moreover, there were negative relationships between social support and depression and between health promoting behaviors and depression. Conclusions: To promote physical and emotional health of unmarried pregnant women, more attention is necessary to increase their social support. A nursing intervention program to increase social support among unmarried pregnant women in needed.