Psychological First Aid (PFA) is an evidence-informed modular approach to help children, adolescents, adults, and families in the immediate aftermath of disaster and terrorism. Individuals affected by a disaster or traumatic incident, whether survivors, witnesses, or responders to such events, may struggle with or face new challenges following the event. PFA was developed by the National Child Traumatic Stress Network and the National Center for PTSD, with contributions from individuals involved in disaster research and response. PFA is designed to reduce the initial distress caused by traumatic events and to foster short- and long-term adaptive functioning and coping. PFA does not assume that all survivors will develop severe mental health problems or long-term difficulties in recovery. Instead, it is based on an understanding that disaster survivors and others affected by such events will experience a broad range of early reactions (e.g., physical, psychological, behavioral, spiritual). Some of these reactions will cause enough distress to interfere with adaptive coping, and recovery may be helped by support from compassionate and caring disaster responders.