Nepenthes sibuyanensis is endemic to Sibuyan Island in the Philippines, where it grows on Mount Guiting-Guiting, neighbouring Mount Mayo, as well as the ridge that connects these two mountains. The altitudinal distribution given for this species varies considerably between sources: Vlastik Rybka, Romana Rybková and Rob Cantley give a range of 1200-1800 m above sea level, while the authors of the describing paper and Stewart McPherson give narrower ranges of 1500-1800 m and 1250-1500 m, respectively. According to Rybka, Rybková and Cantley, the species is sympatric with the tiny N. argentii at around 1600-1770 m. A species resembling N. alata grows on Mount Guiting-Guiting at lower elevations of 800-1000 m; it was described as N. graciliflora by Adolph Daniel Edward Elmer. Nepenthes armin also occurs on Mt. Guiting-Guiting and on a ridge leading to Mt. Mayo, however it is found at lower elevations and within a more restricted area (750 m). Other plant species endemic to the mountain include Lobelia proctorii and Rhododendron rousei. Nepenthes sibuyanensis has no known natural hybrids, although it may hybridise with N. argentii.