Daspletosaurus torosus was named by Russell (1970). Its type specimen is NMC 8506, a partial skeleton, and it is a 3D body fossil. Its type locality is RTMP Quarry 72, Steveville, (NMC), which is in a Campanian fine channel fill sandstone in the Oldman Formation of Canada. It was considered monophyletic by Currie (2000).

It was recombined as Tyrannosaurus torosus by Paul (1988); it was synonymized subjectively with Gorgosaurus libratus by Carr (1995); it was misspelled as Daspletosaurus torrosus by Mader and Bradley (1989), Molnar et al. (1990), Molnar (1991), Currie (1992), Carpenter (1992), Eberth (1997), Carr (1999), Currie (2000), Eberth et al. (2001), Holtz (2001), Rauhut (2003), Currie et al. (2003), Currie (2003), Holtz (2004), Currie et al. (2005), Currie (2005), Malkani (2006), Urban and Lamanna (2006), Cooper et al. (2008), Eberth and Evans (2011), Hone et al. (2011), Lehman and Wick (2013), Dalman (2013), McCrea et al. (2014), Peecook and Sidor (2015), Currie and Koppelhus (2015), Carr et al. (2017), Buckley et al. (2018), Dalman et al. (2018), McDonald et al. (2018) and Yun (2020).