Sospel (French pronunciation: [sɔspɛl]; Mentonasc: Sospèl; Italian: Sospello) is a commune (municipality) and former schismatic episcopal seat (1381-1418) in the Alpes-Maritimes department in southeastern France near the Italian border and not far from Monte Carlo.

The town dates back to the 5th century, when it served as an important staging post on the royal road from Nice to Turin.

During the Western Schism, the Diocese of Ventimiglia (Vintimille in French) was split : the canonical bishop, still residing in Ventimiglia, obedient to the Pope in Rome, controlled the territories dependent of the Italian dogal Republic of Genoa, but an uncanonical line of rival anti-bishops (1381-1418), obedient to the Antipope of Avignon, established their schismatical see 'of Ventimiglia' in Sospel(lo), with sway over the diocese's 'French' territories dependent on the County of Savoy and the lordship of Tende.

After Ventimiglia's diocesan authority was restored in 1412 as the jurisdiction now known as the Diocese of Ventimiglia-San Remo, Sospel was assigned to what is now the Diocese of Nice, France, and its former cathedral was demoted to simple church.

Influenced by its low altitude, Sospel experiences light frosts in winter and cool nights during the summer.