In the US:
National Suicide Prevention Lifeline
A free, 24-hour hotline available to anyone in suicidal crisis or emotional distress. Your call will be routed to the nearest crisis center to you.
The Trevor Project
The Trevor Project is determined to end suicide among LGBTQ youth by providing life-saving and life-affirming resources including a nationwide, 24/7 crisis intervention lifeline, digital community and advocacy/educational programs that create a safe, supportive and positive environment for everyone.
Samaritans centers provide volunteer-staffed hotlines and professional and volunteer-run public education programs, “suicide survivor” support groups and many other crisis response, outreach and advocacy activities.
An anonymous online resource where you can learn about suicide prevention and campus-specific resources.
American Foundation for Suicide Prevention:
A national nonprofit organization dedicated to understanding and preventing suicide through research, education and advocacy, and to reaching out to people impacted by suicide.
A nonprofit organization that cultivates a community for those deeply affected by suicide by offering them a creative outlet to share their story.
Mental Health First Aid USA
A public education program that helps the public identify, understand and respond to signs of mental illnesses and substance use disorders.
A national nonprofit dedicated to preventing suicide through public awareness and education.
International Association for Suicide Prevention
IASP now includes professionals and volunteers from more than fifty different countries. IASP is a Non-Governmental Organization in official relationship with the World Health Organization (WHO) concerned with suicide prevention.
Canadian Association for Suicide Prevention
A resource for survivors as well as anyone in suicidal distress.
To find the nearest crisis center: http://www.casp-acps.ca/crisiscentres.asp
To find the nearest support group: http://www.casp-acps.ca/supportgroups.asp
Centro de Asistencia del Suicida Bs. As. (Argentina)
línea gratuita 135
Centro de Atención al Familiar del Suicida (Argentina)
Centro de Valorização da Vida (Brazil)
Sociedade Portuguesa de Suicidologia (Portugal)
Befrienders Helplines (Italy)
Suicide Ecoute (France)
한국자살예방협회 (Korean Association for Suicide Prevention)
한국자살협회 사이버 상담실 (Korean Suicide Prevention Cyber Counseling)
If you know of good resources available where you live, please add them to the comments section of this post.