Lisboasaurus is a small (400 mm length) genus of Mesozoic crocodylomorph that lived in fresh water.

In the 1960s paleontologists From the Free University Berlin located new vertebrate fossil sites that included the lignite mines of Guimarota, near the town of Leiria, Portugal.

Seiffert, (1970, 1973), described Lisboasaurus as a genus of anguimorph lepidosaur comprising two species, L. estesi and L. mitracostatus.

Milner and Evans, 1991, redescribed L. estesi as a maniraptoran and, more specifically, as an early avialan or troodontid They also cast doubt on the identification of the more poorly preserved L. mistracostatus, considering it a nomen dubium.

Buscalioni and Evans et al. revised this assignment by demonstrating that the material referred to L. estesi was closely allied with an Early Cretaceous crocodylomorph (LH 7991) from Las Hoyas, Spain.