The examination of gill parasites from the freshwater shark Wallago attu Bloch and Schn., 1801 (Siluriformes: Siluridae) in India revealed the presence of a new species of the genus Thaparocleidus Jain, 1952 from the Ganga River, Uttar Pradesh, India. The new species can be discriminated from its congeners by the combination of the following characteristics: accessory piece much smaller than cirrus tube, dorsal anchor with well-developed inner root and small outer root, shaft smoothly bent to form recurved point, inner and outer roots of ventral anchors developed equally so that attain almost equal length, dorsal bar curved in the medial part with expanded lateral ends slightly curved in posterior direction, ventral bar narrowly V-shaped. Thaparocleidus gangus sp. nov. was found to be closely related to T. indicus and T. sudhakari as indicated by their similar morphological appearance. It is a larger worm than T. indicus and T. sudhakari species and can further be separated from them by means of the comparative morphology of the anchors, bars, and cirrus.