Élie Antoine Octave Lignier (25 February 1855, in Pougy – 19 March 1916, in Caen) was a French botanist, known for his work in the field of paleobotany. From 1880 to 1887 he worked as assistant to Charles Eugène Bertrand at the University of Lille. He obtained his doctorate in sciences at Paris, and from 1887 gave lectures in botany at the University of Caen. In 1889 he received the title of professor, and from 1896 served as director of the botanical garden at Caen.