The show, which will air for nine weeks, will be anchored by Josh Elliot and Lara Spencer, with Sam Champion, Robin Roberts and George Stephanopoulos making special appearances.
"It's tremendous that 'GMA' has this opportunity to extend its reach and bring something new to the afternoons," Elliot said in a statement. "It is gratifying to play a role in it, and we genuinely hope our audience will come along for the ride."
The network said the new show will feature celebrities, music performances, pop culture news and other reporting.
"I am beyond excited and honored to be part of this new chapter for the 'Good Morning America' family," Spencer said in a statement.
"Good Afternoon America" will premiere on July 9 at 2 p.m., replacing "The Revolution."