Nymphaeales is an order of plants, consisting of three families, the water lilies and two other families of aquatic plants. It is one of the three orders of basal angiosperms, an early-diverging grade of flowering plants.
All of the species are rhizomatous aquatic herbs with a broad leaf base.
At least 10 morphological characters unite the Nymphaeales. Molecular synapomorphies are also known.
The Plant List recognizes about 70 species in the order, but a phylogenetic study of the genus Nymphaea implies that the number of species could be more than 90. The difference in species numbers is due almost entirely to the difficulty of delineating species in Nymphaea.