This study investigates the role of family and social relationships in cases of attempted suicide in China. Studies, mostly analyzing data from developed countries, have indicated that interpersonal relationships are important predictors of suicidal behaviors. This study’s data were derived from a case-control study in China. Family relationships included relationships with spouses, parents, and parents-in-law. Poor family and social relationships were significantly associated with increased risk of attempted suicide in women and men. Depression and social support significantly mediated the association between interpersonal relationship and attempted suicide. Poor relationship with spouse was significantly associated with an elevated risk of attempted suicide. Relationship with parents-in-law was also significantly associated with attempted suicide in women, whereas family relationships played a more important role than social relationships in suicidal behaviors, especially in men. The findings imply that suicide prevention in China could be conducted from the perspective of improving family relationships, especially husband/wife and parents/daughters-in-law relationships.