"Nepenthes bellii" was formally described by Katsuhiko Kondo in the November–December 1969 issue of the "Bulletin of the Torrey Botanical Club". The designated holotype, "Kondo 11514", was collected on April 14, 1968, from a "pool between Hayangobon & Carrascar" in Surigao Province, Mindanao, at an altitude of 800 m. It was collected by Kondo as part of a 1968 trip to the Philippines alongside J. V. Pancho. The holotype is deposited at the herbarium of the North Carolina Botanical Garden (NCU); isotypes are held at the KC and Nagoya herbaria.