"Nepenthes beccariana" was described by John Muirhead Macfarlane in 1908 based on a specimen collected on Nias, an island located approximately 120 km from the port town of Sibolga. Twenty years later, B. H. Danser synonymised the taxon with "N. mirabilis" in his seminal monograph "The Nepenthaceae of the Netherlands Indies", although he did not see the type specimen of "N. beccariana". In 2000, Jan Schlauer and C. Nepi examined the type specimen of "N. beccariana" and noted significant differences between it and "N. mirabilis", suggesting that it should be restored as a distinct species. Charles Clarke agrees that "N. beccariana" appears to be distinct from both "N. mirabilis" and "N. sumatrana" but notes that if "N. beccariana" is found to be conspecific with "N. longifolia", the latter taxon would become a junior synonym of the former. However, observations of "N. beccariana" at the type locality would need to be carried out to resolve this taxonomic confusion, since the type specimen of "N. beccariana" only consists of fragments of three leaves and three pitchers (two rosette pitchers and one upper pitcher) and is in a damaged state; the leaves are separated from the stem such that their attachment is unknown.