A suicide bomber had detonated himself among Shia Muslim pilgrims in Baghdad, while car bombs targeted an elementary school and a police station in a northern Iraqi village.
The explosions on Sunday began in the Shia Turkomen village of Qabak, just outside the town of Tal Afar, targeting children aged 6 to 12.
The attack that killed a school principle and 12 children was followed by another suicide car explosion near a village police station killing two policemen, Abdul Aal al-Obeidi, Tal Afar's mayor, said adding that the Qabak village attacks wounded another 90 people.
"We and Iraq are plagued by al-Qaeda," al-Obeidi said. "It's a tragedy. These innocent children were here to study. What sins did these children commit?"
Another suicide bomber, this time on foot, blew himself up hours later as Shia pilgrims walked through the largely Sunni neighbourhood of Waziriyah in the north of the Iraqi capital, Baghdad.
At least 12 people were killed and 23 wounded in that attack, according to police and hospital officials.
There was no immediate claim of responsibility, but suicide bombers and car bombs are frequently used by al-Qaeda's Iraq branch.
The armed group, called The Islamic State of Iraq and the Levant, said in a statement on Sunday that it had carried out a September 29 attack which killed seven security force members and wounded more than 60 in the Kurdish region's capital city of Arbil.
The Sunday attacks are the latest in a relentless wave of killing that has made for Iraq's deadliest outburst of violence since 2008.
The mounting death tolls are raising fears that the country is falling back into the spiral of violence that brought it to the edge of civil war in the years after the 2003 US-led invasion.
The UN figures released this week showed that at least 979 people, most of them civilians, were killed last month alone. At least 135 have died violently since the start of October, according to an Associated Press news agency's count.