 The current taxonomic arrangement of the genus Banksia is based on botanist Alex George's 1999 monograph for the Flora of Australia book series. In this arrangement, B. dentata is placed in Banksia subgenus Banksia, because its inflorescences take the form of Banksia's characteristic flower spikes, section Banksia because of its straight styles, and series Salicinae because its inflorescences are cylindrical. There has been debate on which species it is most closely related to. Alf Salkin had noted that B. dentata displays characteristics which are primitive within the genus. Unlike southern banksias, it has small juvenile leaves and broad dentate adult leaves. Alex George concluded initially that its affinities lay with Banksia integrifolia on account of their similar inflorescences. In a morphological cladistic analysis published in 1994, Kevin Thiele placed it in the newly described subseries Acclives along with B. plagiocarpa, B. robur and B. oblongifolia within the series Salicinae. These four species all have follicles which point slightly upwards towards the apex of the flower spike. It was held to be most closely related to B. robur on account of its large undulate leaves. Salkin had also noted that the seedling leaves of B. dentata, B. robur and B. oblongifolia were all similar and roughly linear, suggesting a close relationship. However, this subgrouping of the Salicinae was not supported by George; he discounted a close relationship with B. robur, which he felt was too distinctive. B. dentata's placement within Banksia according to Flora of Australia is as follows:
