Lopha is a genus of marine bivalve molluscs in the family Ostreidae.
The genus Lopha is present from the Triassic period in the Lower Norian age (216.5 ± 2.0 – 203.6 ± 1.5 Mya) to the recent age.
Lopha species have thick, strongly ribbed shells with unequal valves. The margins of the valves have a characteristic zig-zag pattern. The lower valve shows finger-like outgrowths, by which the molluscs adhere to the substrate. These molluscs are stationary, epifaunal, suspension feeders, as they feed by filtering sea water to extract the nutrients.