The species were first named by Andrew Leith Adams in 1863 from remains found in caves in Malta and were assigned to the living genus Myoxus.

[2] Leithia was proposed in 1896 by Richard Lydekker as a new genus, suggesting an arrangement currently recognised as the subfamily Leithiinae; the names honour Leith Adams.

[5] L. melitensis reached a total size comparable to a cat[6] or a rabbit,[7] with an estimated body mass of approximately 1 kilogram (2.2 lb).

[8] Compared to Eliomys, the skull morphology of L. melitensis is much more robust, particularly the zygomatic region (indicating the presence of large masseter muscles in life) and the pterygoid flange.

[13] It has been suggested by some that the ancestors Leithia arrived in Sicily during the Late Miocene (Messinian) or Pliocene, but this is not preserved in the fossil record.