The blast in the Obeidi area also wounded at least 19 people, the officials said.
There was no immediate claim of responsibility for the attack, but in Iraq suicide bombings are a tactic almost exclusively used by the Islamic State jihadist group.
IS considers Shiites to be heretics, and frequently targets them with bombings in crowded areas of the capital.
IS overran large areas north and west of Baghdad last year, and while Iraqi forces have retaken significant territory north of the capital, much of the country's west remains under jihadist control.