Wright faced a challenge in designing Unity Temple in that there was a very strict budget of $35,000. He chose poured concrete as the primary material mostly because it was relatively inexpensive. However, over the course of construction, he found concrete to be quite beautiful. Unlike other architects who built with concrete and then covered it up with other materials, Wright loved the sculptural quality and texture of it. He made all of the architectural details of Unity Temple with concrete.

Wright designed the structure with the democratic ideals of Unitarianism in mind. The shape of the main worship building is a Greek cross (a cross shaped like a plus sign +) inside a square, and there is an entrance on two sides. Wright incorporated the idea of creating a community through how the space is used. The benches for worship are arranged around a square, so everyone can see everyone else during the service. Beautiful colored skylights and high windows let sunlight in from above while keeping the focus on the activities inside the building. Wright later said of this building, "Unity Temple is where you will find the first real expression of the idea that the space within the building is the reality of that building." The educational wing of the building is attached to the worship space and contains classrooms and a banquet hall.