This article follows Chan et al. (2021) and WoRMS in placing Thoracica as an infraclass of Thecostraca and in the following classification of thoracicans down to the level of family:[3][4]
- Infraclass Thoracica Darwin, 1854
- Superorder Phosphatothoracica Gale, 2019
- Order Iblomorpha Buckeridge & Newman, 2006
- Family Iblidae Leach, 1825
- Family Idioiblidae Buckeridge & Newman, 2006
- Order †Eolepadomorpha Chan et al., 2021
- Family †Eolepadidae Buckeridge, 1983
- Family †Praelepadidae Chernyshev, 1930
- Superorder Thoracicalcarea Gale, 2015
- Order Balanomorpha Pilsbry, 1916
- Superfamily Balanoidea Leach, 1817
- Family Balanidae Leach, 1817
- Family Pyrgomatidae Gray, 1825
- Superfamily Chthamaloidea Darwin, 1854
- Family Catophragmidae Utinomi, 1968
- Family Chionelasmatidae Buckeridge, 1983
- Family Chthamalidae Darwin, 1854
- Family Pachylasmatidae Utinomi, 1968
- Family Waikalasmatidae Ross & Newman, 2001
- Superfamily Coronuloidea Leach, 1817
- Family Austrobalanidae Newman & Ross, 1976
- Family Bathylasmatidae Newman & Ross, 1971
- Family Chelonibiidae Pilsbry, 1916
- Family Coronulidae Leach, 1817
- Family Tetraclitidae Gruvel, 1903
- Superfamily Elminioidea Chan et al., 2021
- Family Elminiidae Foster, 1982
- Superfamily †Pachydiadematoidea Chan et al., 2021
- Family †Pachydiadematidae Chan et al., 2021
- Order Calanticomorpha Chan et al., 2021
- Family Calanticidae Zevina, 1978
- Family †Cretiscalpellidae Buckeridge, 1983
- Family †Titanolepadidae Gale & Sørensen, 2015
- Order Pollicipedomorpha Chan et al., 2021
- Family Lithotryidae Gruvel, 1905
- Family Pollicipedidae Leach, 1817
- Family †Zeugmatolepadidae Newman, 1996
- Order Scalpellomorpha Buckeridge & Newman, 2006
- Superfamily Lepadoidea Chan et al., 2021
- Family Heteralepadidae Nilsson-Cantell, 1921
- Family Lepadidae Darwin, 1852
- Family Malacolepadidae Hiro, 1937
- Family Poecilasmatidae Annandale, 1909
- Family Rhizolepadidae Zevina, 1980
- Superfamily Neolepadoidea Chan et al., 2021
- Family Neobrachylepadidae Newman & Yamaguchi, 1995
- Family Neolepadidae Yamaguchi, Newman & Hashimoto, 2004
- Family Neoverrucidae Newman, 1989 in Hessler & Newman, 1989
- Family Probathylepadidae Ren & Sha, 2015
- Superfamily Scalpelloidea Chan et al., 2021
- Family Scalpellidae Pilsbry, 1907
- Family †Proverrucidae Newman, 1989 in Hessler & Newman, 1989
- Order Verrucomorpha Pilsbry, 1916
- Family Verrucidae Darwin, 1854
- Family †Eoverrucidae Gale, 2020
- Order †Archaeolepadomorpha Chan et al., 2021
- Family †Archaeolepadidae Gale, 2019
- Family †Myolepadidae Gale, 2015 in Gale & Sørensen, 2015
- Family †Stramentidae Withers, 1920
- Order †Brachylepadomorpha Withers, 1923
- Family †Brachylepadidae Woodward, 1901
