The attacks come amid growing tensions between the Shiite-led government and minority Sunnis.
Police and hospital officials say the deadliest attack was near a bus stop in the sprawling neighbourhood of Sadr City where at least seven people were killed and 20 wounded.
Officials say in all 11 bombings struck Baghdad, as well as the cities of Kirkuk and Tarmiyah.
Nobody claimed responsibility for the attacks, but they bore the hallmark of al-Qaeda in Iraq and other Sunni insurgent groups.