Stephen was the first Christian martyr, and his stoning is recorded in Acts 6-7. He was one of the seven deacons appointed by the apostles to serve the early church. Stephen was described as a man "full of faith and of the Holy Spirit" (Acts 6:5) who performed great wonders and signs among the people.
Stephen was brought before the Sanhedrin on charges of blasphemy. He delivered a lengthy speech recounting Israel's history and accused the council of resisting the Holy Spirit and betraying the Righteous One. Enraged, the members of the council dragged him out of the city and stoned him to death (Acts 7:57-60). As he was dying, Stephen prayed, "Lord Jesus, receive my spirit," and "Lord, do not hold this sin against them."
Peter and James were martyred by other means: James was killed by the sword under Herod Agrippa (Acts 12:2), and tradition holds that Peter was crucified. Paul (who was present at Stephen's stoning as a consenting witness) was later executed in Rome but was not stoned to death in Acts. Stephen is the figure in Acts who was explicitly stoned for his faith.