Samydaceae are a family of flowering plants formerly placed in the polyphyletic Flacourtiaceae. Samydaceae have sometimes been segregated from Flacourtiaceae (e.g., by Bentham and Hooker) as the group with well-developed hypanthia, and this tradition has been maintained in many African floras. Recent analyses based on both morphological and molecular data indicate that Samydaceae are a monophyletic and monothetic group related to Salicaceae, which now also include many former Flacourtiaceae. Some authors (e.g., Chase et al., 2002) even place Samydaceae in a broader Salicaceae. However, Samydaceae share many symplesiomorphies with other Malpighialean families, such as Passifloraceae, and show few obvious morphological connections to Salicaceae.

Like many other closely-related taxa in the Malpighiales, Samydaceae have introrse anther dehiscence, parietal placentation, and arillate seeds. They also have synapomorphies which are useful for field identification: pellucid-punctations and/or -lines (usually in the leaves) and deciduous leaf teeth (theoid type). Almost all members of the family have minute flowers. The largest genus in the family is Casearia, which has more than 180 species, and the number of species coupled with the size of the flowers has left the family largely unstudied.

The genus Casearia is pantropical, Osmelia and Pseudosmelia are from Indo-Malesia, Ophiobotrys and Trichostephanus are from tropical Africa, and all of the other genera are neotropical.