Lacertilia was named by Owen (1842). It is extant. It was considered monophyletic by Prothero and Estes (1980).

It was corrected as Lacertia by Owen (1854); it was reranked as the suborder Lacertae by Gadow (1898); it was synonymized subjectively with Sauria by Hay (1902), Kuhn (1966), Dundee (1989); it was corrected as Lacerti by Jaekel (1910); it was reranked as the order Lacerti by Jaekel (1911); it was synonymized subjectively with Sauria by Perrier (1928), Sulimski (1975), Lingham-Soliar (1994); it was reranked as the unranked clade Lacertilia by Sullivan (1986), Nicholls and Meckert (2002), Augé and Rage (2006); it was reranked as the suborder Lacertilia by Zittel (1890), Woodward (1898), Osborn (1903), Lambe (1908), Swinton (1934), Roxo (1937), Kuhn (1946), Huene (1954), Miller (1967), Seiffert (1975), Carroll and Galton (1977), Prothero and Estes (1980), Thurmond and Jones (1981), Carroll (1982), Estes (1983), Stritzke (1983), Carroll (1988), Gao and Fox (1991), Gao and Fox (1996), Frank and Ramus (1996), Gao and Hou (1996), Peng et al. (2001), Venczel and Stiuca (2008), Böhme (2010).

It was assigned to Sauria by Owen (1859); to Lepidosauria by Zittel (1890); to Autosauri by Gadow (1898); to Squamata by Osborn (1903), Osborn (1904); to Lyognatha by Jaekel (1910); to Lyognathi by Jaekel (1911); to Squamata by Miller (1967); to Sauria by Estes (1983); to Sauria by Sullivan (1986); to Squamata by Nicholls and Meckert (2002); to Reptilia by Owen (1854), Owen (1860), Owen (1861), Cope (1871), Leidy (1873), Cope (1875), Günther (1886), Augé and Rage (2006); and to Squamata by Woodward (1898), Osborn (1903), Lambe (1908), Swinton (1934), Roxo (1937), Kuhn (1946), Huene (1954), Seiffert (1975), Carroll and Galton (1977), Prothero and Estes (1980), Thurmond and Jones (1981), Carroll (1982), Stritzke (1983), Carroll (1988), Gao and Fox (1991), Gao and Fox (1996), Frank and Ramus (1996), Gao and Hou (1996), Peng et al. (2001), Venczel and Stiuca (2008), Böhme (2010).