Evangelical Free Church of Diamond Bar began as a home Bible study in January 1967 with six families. By the end of that first year they had started meeting on Sundays as a church in a neighboring home.
The growing church met in several locations, including local schools and the YMCA before renting the site of the original Diamond Bar Ranch house. A local Christian realtor secured the property for development in 1980, donating a portion of the land to the church.Construction of the first building began in 1982 and was completed in April 1983. A two story classroom building was added in 1992 and a new auditorium was completed in 2000. Over the years the church has grown from the original six families to over 300 families, serving over a dozen surrounding communities. Evangelical Free Church of Diamond Bar has also planted a thriving daughter church in the Corona Valley community of Eastvale.