Peirosauridae was named by Gasparini (1982). It was considered monophyletic by Larsson and Sues (2007), Turner and Sertich (2010).

It was reranked as the unranked clade Peirosauridae by Geroto and Bertini (2019), Nicholl et al. (2021), Ruiz et al. (2024), Novas et al. (2025).

It was assigned to Crocodilomorphi by Gasparini et al. (1991); to Metasuchia by Sereno et al. (2001); to Peirosauroidea by Carvalho et al. (2004); to Crocodyliformes by Gasparini et al. (2006); to Mesoeucrocodylia by Turner (2006), Sertich and O'Connor (2014), Lamanna et al. (2019); to Notosuchia by Turner and Sertich (2010), Pol et al. (2012), Pol et al. (2014), Barrios et al. (2016), Nicholl et al. (2021), Paulina-Carabajal et al. (2021); to Crocodylomorpha by Agnolín et al. (2023); to Sebecia by Larsson and Sues (2007), Geroto and Bertini (2019), Ruiz et al. (2024); and to Peirosauria by Novas et al. (2025).