The patron saints of San Sossio Baronia are Saint Peter Martyr, celebrated on 29 April, and Saint Sossius, Levite and Martyr, venerated in the parish church of Santa Maria Assunta.
The parish of Santa Maria Assunta was linked from its origin to the diocese of Trevico, and a parish community was already present in San Sossio in 1308; the municipality also holds the churches of San Michele Arcangelo, San Francesco Saverio and San Leonardo, the Fontana Tre Cannelle and Crucinova («Croce Nova»).
