Zacchaeus (sometimes spelled Zaccheus; Ancient Greek: Ζακχαῖος, Zakkhaîos; Hebrew: זכי, "pure, innocent") was a chief tax-collector at Jericho in the Bible. He is known primarily for his faith in climbing a sycamore tree to see Jesus, and also his generosity in giving half of all he possessed. A descendant of Abraham, he was an example of Jesus's personal, earthly mission to bring salvation to the lost. Tax collectors were despised as traitors (working for the Roman Empire, not for their Jewish community), and as being corrupt. His story is found in the Gospel of Luke.

Because the lucrative production and export of balsam was centered in Jericho, his position would have carried both importance and wealth. In the account, he arrived before the crowd who were later to meet with Jesus, who was passing through Jericho on his way to Jerusalem. He was short in stature and so was unable to see Jesus through the crowd (Luke 19:3). Zacchaeus then ran ahead and climbed a sycamore tree along Jesus's path. When Jesus reached the spot he looked up at the sycamore tree (actually a sycamore-fig Ficus sycomorus), addressed Zacchaeus by name, and told him to come down, for he intended to visit his house. The crowd was shocked that Jesus, a religious teacher/prophet, would sully himself by being a guest of a sinner.