Macrochelys was named by Gray (1856) [Webb (1995; reference # 50687) demonstrated that Macrochelys is the senior synonym of Macroclemys and both were published in 1856 (not 1855 as commonly stated) [Richard Hulbert, Apr. 2014]]. It is extant. It was considered monophyletic by Thomas et al. (2014).

It was corrected as Macroclemys by Frank and Ramus (1996) and Anquetin et al. (2009).

It was assigned to Testudines by Anquetin et al. (2009); to Chelydridae by Cope (1875), Cope (1884), Hay (1908), Whetstone (1978), Carroll (1988), Frank and Ramus (1996), Knauss et al. (2011), Thomas et al. (2014) and van Dijk et al. (2014); and to Chelydridae by Joyce (2016).