Ammah was a Nephite missionary among the Lamanites, around 90–77 B.C., a companion of Aaron and the sons of Mosiah. He is named when the voice of the Lord directs Ammon to the land of Middoni, where Aaron, Muloki, and Ammah are in prison (Alma 20:2).
Before that imprisonment, Ammah was preaching at the village of Ani-Anti, where Aaron found him and Muloki teaching. Meeting resistance, they departed to Middoni, where few believed and Aaron and several others were taken and cast into prison (Alma 21:11-14). When Ammon found them, they were naked, their skins worn from being bound with strong cords, and they had suffered hunger, thirst, and other afflictions, having been driven from house to house before being imprisoned for many days (Alma 20:29-30).
Lamoni found favor with the king of Middoni and the prisoners were brought out; they were then fed and clothed (Alma 20:28; 21:14). After their release Ammah and his companions went forth again, led by the Spirit, preaching in the synagogues of the Amalekites and assemblies of the Lamanites, and brought many to a knowledge of the truth (Alma 21:16-17).