According to police officer Dost Mohammad, the explosion Saturday took place outside a mosque in the Kali Bari area of the city.
He said a woman was among the wounded, who were rushed to a nearby hospital.
Mohammad said the area was nearly deserted at the time of the early morning blast, AP reported.
No one immediately claimed responsibility for the attack.
Peshawar, capital of Khyber Pakhtunkhwa province, is surrounded by lawless tribal regions that have served as a sanctuary for militants for decades. Militants have targeted the city for years.