A Christian mission is an organized effort to carry on evangelism or other activities, such as educational or hospital work, in the name of the Christian faith. Missions involve sending individuals and groups across boundaries, most commonly geographical boundaries. Sometimes individuals are sent and are called missionaries, and historically may have been based in mission stations. When groups are sent, they are often called mission teams and they undertake mission trips. There are a few different kinds of mission trips: short-term, long-term, relational and those that simply help people in need. Some people choose to dedicate their whole lives to mission.

In Christianity, evangelism or witnessing is the act of preaching the gospel with the intention of sharing the message and teachings of Jesus Christ. It is sometimes associated with Christian missions.