The Southwest's largest Reform Jewish congregation, at 8500 Hillcrest Road, is building a new 450-seat chapel, a new wing for the Early Childhood Education Center and additional learning spaces.
The expansion also includes improvements to the 57-year-old sanctuary.
The new chapel will combine nature and worship, including a giant glass wall facing the Nasher Family Atrium.
Dallas Mayor Mike Rawlings attended Sunday's ceremony and commended the congregation for its history and community.
"This temple has a great heritage and a wonderful gift that it has given to this city," the mayor said.
The groundbreaking celebration is in conjunction with Rabbi David Stern's 25th anniversary at Temple Emanu-El.