Bayog is a 3rd class municipality in the province of Zamboanga del Sur, Philippines.

Potential tourist attractions in Bayog include the 90-foot (30 m) Buco Falls, the Sigacad Hot Spring in Barangay Sigacad, and the Balumbunan Caves, which feature thousands of exotic birds.

It was in the year 1953, that large numbers of immigrants started settling permanently in this area which was then sparsely populated by the native Subanen. Thus, barrio Bayog came into existence under the Municipality of Malangas. Bayog was adopted as the official name of the barrio, as this place was originally known to the natives due to the abundance of the “Bayog” trees in the area.

Opportunities in agriculture, business and employment attracted more settlers into the area, particularly during the year 1957 and 1958. The influx of settlers was given more impetus when the SAMAR MINING COMPANY (SAMICO) constructed the existing forty two (42 km) kilometers SAMICO road from Bobuan to its wharf in Pamintayan. By 1959, Bayog was already quite big for a barrio. So another barrio was created which is now the present barangay Kahayagan. When the municipality of Buug (also a former barrio of Malangas) was created in 1960, barangay Bayog and Kahayagan were among the barrios under it.