It is the latest in a surge in violence that has been the most serious challenge to the government's efforts to achieve stability across Iraq.
The attacks came as Iraqi Shiites were celebrating the birthday of Imam Ali, the cousin and son-in-law of the Prophet Mohammed and Shiite Islam's most sacred martyr.
In the neighbourhood of Sadr City, one bomb went off in the morning hours, killing four people and wounding six, police officials said.Another car bomb elsewhere in Sadr City exploded near a cluster of homes, killing two people and wounding seven.
Television footage from one of the Sadr City attacks showed a thick cloud of smoke rising from the blast area where several cars were on fire.
A short while later, a bomb exploded in a commercial street in the eastern district of Jamila, killing three people and wounding 10. Police said a fourth car bomb went off near a traffic police office in eastern Baghdad, killing four people, including a traffic policeman. Seven people were wounded in that attack.
Haithem Kadhum, owner of a juice shop in Jamila who was wounded in the attack there, said he was in his store when he heard a big explosion.
He was told the blast was in his home neighbourhood of Sadr City so rushed to his car to go to check on his family.
But as he was driving through Jamila, another explosion went off near him. The flying shrapnel wounded him in the shoulder.
Another bomb exploded at a square in the centre of the capital, killing two people.