This dinosaur measured around 24 feet in length. It had paired triangular plates down its spine, and four pairs of spikes on the end of its tail. This configuration closely resembles that of its relative, the African Kentrosaurus. Many books claim that Dacentrurus was a small stegosaur, when in fact finds such as a 4.9-foot long pelvis suggest that Dacentrurus was among the largest of them. Although Dacentrurus is considered to have the same proportions as a Stegosaurus, Dacentrurus' plate and spike configuration is known to be rather different, as Dacentrurus has both two rows of small plates and two rows of longer spines along its back. Its closest relative within Stegosauria is the recently described Miragaia, and the two are united in the subfamily Dacentrurinae.