This thesis deals with the topic of mental health in a family whose member suffers from post-traumatic stress disorder (PTSD). The focus of the paper is on post-traumatic stress disorder as one of the more severe mental disorders which, in addition to the numerous symptoms that the individual who suffers from PTSD deals with, also affects the mental health of family members of the individual who suffers from PTSD. The thesis describes and analyzes the mental health factors of children and partners of people who are suffering from post-traumatic stress disorder. Their psychological and emotional reactions, the long-term consequences caused by the PTSD of the family member who is suffering from it and the behavior of the affected person, which can have an effect at psychological health of children and partners, are described in more detail. In the world and in the Republic of Croatia, certain developments have been achieved in the field of mental health support in families whose members suffers from PTSD. Examples of good practice of mental health support, which can be used as guidelines for work, are presented in this paper. Special attention is paid to the role and tasks of the social worker in supporting the mental health of PTSD sufferers and family members.