The Sahara and Sahel Observatory (OSS) is an international, intergovernmental organization operating in Africa's Sahara-Sahel region. OSS was founded in 1992 in Paris and moved its headquarters to Tunis (Tunisia) in 2000.

OSS members include 22 African countries, five non-regional countries, ten organizations (incl. sub-regional organizations representing West Africa, East Africa and North Africa), and a non-governmental organization.