Phyllonorycter lyoniae is a moth of the Gracillariidae family, described by Tosio Kumata in 1963. It is known from the islands of Shikoku, Kyushu and Honshu in Japan. The wingspan is 6.5–7 mm. The larvae feed on Lyonia ovalifolia var. elliptica. They mine the leaves of their host plant, that is, they live in and eat the leaf tissue of plants. The mine is ptychonomous and situated along the margin or rarely on the space between two veins of the lower surface of the leaf.