Sinemys is an extinct genus of turtle from the Late Jurassic to Early Cretaceous of China and Japan. Three species have been named: S. lens, the type species, from the Kimmeridgian-Tithonian of Shandong; S. gamera, from the Valanginian-Albian of Nei Mongol; and S. wuerhoensis, from the Aptian-Albian of Xinjiang.