Opisthocoelicaudia was named by Borsuk-Bialynicka (1977). It is the type genus of Opisthocoelicaudiinae. It was considered monophyletic by Maryanska (2000).

It was assigned to Euhelopodinae by Borsuk-Bialynicka (1977); to Camarasaurinae by Coombs and Molnar (1981); to Titanosaurinae by Salgado and Martínez (1993); to Camarasauridae by Kielan-Jaworowska (1984), Carroll (1988), McIntosh (1990), Currie (1992) and McIntosh (1997); to Opisthocoelicaudidae by Dong (1998) and Bonaparte (1999); to Titanosauroidea by Upchurch (1995), Upchurch (1995), Upchurch (1997) and Powell (2003); to Titanosauridae by Salgado and Coria (1993), Salgado et al. (1997), Smith et al. (2001), Currie et al. (2003), Calvo and González Riga (2003) and Apesteguía (2005); to Titanosauria by Wilson and Sereno (1998), Moser et al. (2006) and Wilson and Upchurch (2009); to Lithostrotia by Ksepka and Norell (2010); to Eutitanosauria by Filippi et al. (2011); to Opisthocoelicaudinae by Franco-Rosas et al. (2004), Calvo et al. (2007) and González Riga and Ortiz David (2014); to Somphospondyli by Xing et al. (2015); to Saltasauridae by Upchurch et al. (2004), Royo-Torres et al. (2006), Wilson and Mohabey (2006), Zaher et al. (2011), Grellet-Tinner et al. (2011), D'Emic (2012), Coria et al. (2013), Mannion et al. (2013), Mocho et al. (2014), González Riga et al. (2016), Poropat et al. (2016), Gorscak et al. (2017) and Páramo et al. (2020); and to Opisthocoelicaudiinae by McIntosh (1990), Sereno (1998), Maryanska (2000), Wilson (2002), Wilson and Upchurch (2003), Salgado (2003), You et al. (2004), Wilson (2005), Curry Rogers (2005), Calvo et al. (2007), González Riga et al. (2009), Suteethorn et al. (2010) and Navarro et al. (2022).