The explosions, in confessionally-mixed neighbourhoods of Baghdad, come amid the worst surge in bloodshed in more than five years, raising fears Iraq is slipping back into the sectarian violence that left tens of thousands dead in 2006 and 2007.
The blasts, which also hit a restaurant and a market for vehicle spare parts, struck during the morning rush hour.
The attack at the restaurant was a suicide bombing, while the other two explosions were caused by vehicles rigged with explosives.
More than 1,000 people were killed in January of this year, according to government data, as security forces have struggled to curb bombings while also battling jihadists and other militants who have seized territory in the western Anbar province.
Foreign leaders and diplomats have urged the Shiite-led government to reach out to Iraq's disaffected Sunni minority, but with parliamentary elections looming in April, Prime Minister Nuri al-Maliki has taken a hard line.