The deadliest single attack was a car bombing in the Hurriya district which killed nine people and wounded 30, a police colonel and a hospital official said.
A bomb also exploded near a car park in Al-Obeidi neighbourhood in the east of the city, killing two and wounding seven, a police officer and a medic at Kindi hospital said.
A roadside bomb targeted a police patrol near Zeidan, west of the capital, and another went off in Taji to the north, killing two members of the security forces and two civilians respectively.
In Jisr Diyala, a suburb on Baghdad's southeastern edge, gunmen stormed a home, killing the owner and his son, police said without elaborating on the circumstances.
Violence levels have generally receded in Baghdad in recent months, after government and allied forces retook swathes of land north and south of the capital from the Islamic State group.
A years-old nightly curfew was even lifted a month ago, but sporadic attacks continue and the government is still engaged in fierce fighting against the jihadists just a few miles west of Baghdad on the fringes of Anbar province, an IS bastion.