Background: A large number of women are employed in the labor market. This phenomenon has widely supplanted the traditional family model of full-time working fathers and full-time housewives with the dual-income family model. Most nurses have both family and work responsibilities and hope to balance these two aspects of their lives. Work–family conflict (WFC) is thus a significant issue faced by professional nurses. Purposes: This study examines the relationship between WFC and job performance in the nursing context and explores the moderating effects of different sources of social support. Methods: This study questionnaire used a self-reporting scale. To avoid common method variance, research data were collected at two time points. Five hundred twenty questionnaires were sent to nurses working at five hospitals in Taiwan, and 501 were returned, of which 495 were valid and used in analysis. Hierarchical regression analysis was used to test study hypotheses. Results: Study findings were (a) degree of family-to-work conflict influenced job performance negatively, (b) level of WFC did not significantly affect job performance, (c) support from friends strengthened the negative effect of family-to-work conflict on job performance, and (d) support from coworkers weakened the relationship between WFC and job performance. Conclusions/Implications for Practice: It is hoped that the findings of this study will be useful for nursing managers, organizations, and future research. Hospital organizations and nursing departments have a positive role to play in fostering an organizational culture that helps its staffs balance work and family responsibilities. A strategy of human resource management that is consistent with the demands of nurses may help reduce WFC.