At the opening of worship services, many Unitarian (and Unitarian Universalist) congregations light a flame inside a chalice. This flaming chalice has become a well-known symbol of Unitarianism. The symbolism is not precise, but historically the chalice can be seen as a symbol for sharing among all people and the flame as a symbol for respect for truth.

The symbol had its origins in a logo designed by Austrian refugee Hans Deutsch for the Unitarian Service Committee (USC) in 1941. In occupied Europe during World War II, the flaming chalice became an underground symbol for assistance in helping Unitarians, Jews, and other people escape Nazi persecution.

After 1941, the flaming chalice symbol spread throughout Unitarianism in North America and the rest of the world. The symbol gradually became more than a printed logo; eventually congregations began displaying the symbol in their worship spaces. Along the way, three-dimensional chalices were made to be lit during worship services.