Purpose: The purpose of this study was to identify the moderating effect of social support on the relationship between violence experiences and violence responses of psychiatric nurses. Methods: In this descriptive study, 211 psychiatric nurses were recruited from twelve psychiatric hospitals. A structured self-report questionnaire was used to measure the study variables. Data were analyzed using descriptive statistics, independent t-test, one-way ANOVA, Pearson’s correlation coefficients, and a series of multiple linear regression analyses based on Baron and Kenny’s method with the SPSS 24.0 program. Results: Violence responses positively correlated with violence experiences (r=.15, p=.031), but negatively correlated with social support (r=-.25, p<.001). Social support was a significant variable on violence responses (β=-.26, p<.001). Social support did not moderate effect (β=-.06, p=.377). However family support was significant in controlling emotional responses to psychiatric nurses’ experience of verbal violence (β= -.15, p=.027). Friends support was significant in controlling social responses to psychiatric nurses experienced verbal violence (β=-.14, p=.041). Conclusion: Our study findings indicate a need to provide social support for preventing and alleviating violence responses of psychiatric nurses.