Work-family conflict (WFC) which is a two-sided incompatibility between the demands of work and family roles can be detrimental to individuals, families, and organizations and it is linked to negative consequences. Hence, the aim of the present study was to determine the relationship of the five-factor model of personality and negative affectivity with teachers’ work-family conflict. The population of the study comprised female teachers in Najaf Abad in 2012-2013 academic year. Random sampling method was used and 200 teachers were selected. The instrumentation comprised multi-dimensional work-family conflict scale (Carlson et al.), NEO personality inventory, as well as Positive and Negative Affect Schedule (PANAS) (Watson et al.). The data were analyzed through Pearson correlation coefficient and multiple regression analysis. Results showed that work-family conflict was positively related to negative affectivity (r=0.33) and neuroticism (r=0.25) and was negatively correlated with extraversion (r=-0.21), (P<0.05). However, work-family conflict had no relationship with agreeableness, conscientiousness, and openness to experience. In addition, negative affectivity, neuroticism, and agreeableness explained 32 percent of the variance in work-family conflict. The findings indicated that elevated levels of negative affect and low levels of extraversion increased teachers’ work-family conflict. In order to minimize the negative outcomes of work-family conflict, it is important to familiarize teachers with scientific management of WFC and provide full support to teachers.