One bomb hit the mainly Shi'ite Amil district in the southwest of the city around dusk, killing eight people and wounding 27. The other hit a bus garage in Doura in the south of the capital, killing three people.
Northeast of Baghdad, in the town of Balad Roz, a third car bomb killed two people, local police said.
There was no immediate claim of responsibility but Islamic State fighters who control large parts of western and northern Iraq frequently set off bombs in the capital.
Iraqi security forces and mainly Shi'ite militias are struggling to contain the hardline Sunni Islamist militants in Anbar province west of Baghdad. To the north, they are battling for full control of the town of Baiji and its nearby refinery.
