Ilog, officially the Municipality of Ilog, is a 2nd class municipality in the province of Negros Occidental, Philippines. According to the 2015 census, it has a population of 57,389 people. 

Founded by the Augustinian friars Gerónimo Marín and Francisco Bustos on May 16, 1584, it was the first capital of the historical military district/province of Negros in the late 18th century. The name Ilog (or Ylog, Tagalog for “river”) was recommended by a Tagalog guide of the Spaniards because the place was entirely surrounded by the longest river on the whole Negros Island, the Hilabangan River. The first inhabitants of Ilog are mostly migrants from Panay island.