Joanna is a feminine given name deriving from Koinē Greek: Ἰωάννα, romanized: Iōanna from Hebrew: יוֹחָנָה, romanized: Yôḥānāh, lit. 'God is gracious'. Variants in English include Joan, Joann, Joanne, and Johanna. Other forms of the name in English are Jan, Jane, Janet, Janice, Jean, and Jeanne.

The earliest recorded occurrence of the name Joanna, in Luke 8:3, refers to the disciple "Joanna the wife of Chuza," who was an associate of Mary Magdalene. Her name as given is Greek in form, although it ultimately originated from the Hebrew masculine name יְהוֹחָנָן Yəhôḥānān or יוֹחָנָן Yôḥānān meaning 'God is gracious'. In Greek this name became Ιωαννης Iōannēs, from which Iōanna was derived by giving it a feminine ending. The name Joanna, like Yehohanan, was associated with Hasmonean families. Saint Joanna was culturally Hellenized, thus bearing the Grecian adaptation of a Jewish name, as was commonly done in her milieu.

At the beginning of the Christian era, the names Iōanna and Iōannēs were already common in Judea. The name Joanna and its equivalents became popular for women "all at once" beginning in the 12th century in Navarre and the south of France. In England, the name did not become current until the 19th century.

The original Latin form Joanna was used in English to translate the equivalents in other languages; for example, Juana la Loca is known in English as Joanna the Mad. The variant form Johanna originated in Latin in the Middle Ages, by analogy with the Latin masculine name Johannes. The Greek form lacks a medial -h- because in Greek /h/ could only occur initially.

The Hebrew name יוֹחָנָה Yôḥānāh forms a feminine equivalent in Hebrew for the name Joanna and its variants. The Christian Arabic form of John is يوحنّا Yūḥannā, based on the Judeo-Aramaic form of the name. For Joanna, Arabic translations of the Bible use يونّا Yuwannā based on Syriac ܝܘܚܢ Yoanna, which in turn is based on the Greek form Iōanna.

Sometimes in modern English Joanna is reinterpreted as a compound of the two names Jo and Anna, and therefore given a spelling like JoAnna, Jo-Anna, or Jo Anna. However, the original name Joanna is a single unit, not a compound. The names Hannah, Anna, Anne, Ann are etymologically related to Joanna just the same: they are derived from Hebrew חַנָּה Ḥannāh 'grace' from the same verbal root meaning 'to be gracious'.