In Greek mythology, Myrrha was the daughter of Theias, the King of Assyria, and mother of Adonis by him. Two different versions of Adonis' birth existed.

1. The most commonly accepted version is that Aphrodite urged Myrrha to commit incest with her father, Theias. Myrrha's nurse helped with the scheme. When Theias discovered this, he flew into a rage, chasing his daughter with a knife. The gods turned her into a myrrh tree and Adonis eventually sprung from this tree.
2. It was also said that Myrrha fled from her father and Aphrodite turned her into a tree. Adonis was then born when Theias shot an arrow into the tree or when a boar used its tusks to tear the tree's bark off.

In Ovid's version of the story, Myrrha's father is Cinyras and she is able to sleep with him by disguising herself as a new concubine. This is probably the version that Dante had in mind when, in the Divine Comedy, he sees her shade suffering rabies for all eternity with the other impersonators in the eighth circle of Hell.

In biology, Myrrha is a genus of ladybird beetle.