Protestant free churches see themselves as churches or community movements based on the Reformation. They are united with other Christians by the "Apostles' Creed" as a common basis of faith. The Bible is of great importance, and church life is not only supported by the few full-time staff, but predominantly by volunteers.

Members are not "born into" the free churches, but become members when they profess their Christian faith. For this reason, many Protestant free churches do not baptize infants. They do not levy church taxes, but are financed by voluntary donations.

The sphere of activity of the Evangelical Free Churches usually extends far beyond the city limits, so that numerous other congregations have sprung up from the Wiesbaden congregations. Many free churches work together at a national level in the "Association of Evangelical Free Churches" (VEF, founded in 1926).

In Wiesbaden, the free churches carry out joint activities as part of the "Evangelical Alliance". The impetus for founding the "Freie Christliche Schule Wiesbaden" (Free Christian School Wiesbaden) came not only, but to a large extent, from free-church Christians in the "Evangelical Alliance". There is also cooperation with Protestant Christians with a regional church background, primarily on a personal level. Individual free churches are members of the "Working Group of Christian Churches" at federal, state or regional level.

Increasingly, new, foreign-language free churches of very different cultures are also emerging in Wiesbaden as a result of migration movements. Wiesbaden's Evangelical Free Churches include the Baptist Church, the Evangelical Methodist Church, the Seventh-day Adventists, the Free Evangelical Church, the Salvation Army, the Free Christian Church and the Wiesbaden Christian Center.