Rania Aram died on Thursday after being hit by a bullet in the neck as she stood in front of her house in the Khan Yunus refugee camp.
Witnesses said the shot was fired from an army position on the outskirts of the illegal Jewish settlement, Gush Katif.
Some 23 Palestinian children have been killed since 30 September – the majority receiving bullets in the chest, neck and head.
On 30 September, 15 Palestinian children were killed within hours of each other.
Israeli soldiers wounded
Four Israeli soldiers were wounded in a mortar attack on an army base near a Jewish settlement in the southern Gaza Strip on Thursday. The attack was claimed by the Palestinian resistance movement Hamas.
Hamas claimed responsibility for
Palestinian fighters opened fire at an Israeli Defence Force (IDF) post near the illegal settlement of Morag and fired mortar shells at the post, an Israeli military source said.
Four soldiers were injured, she added.
Hamas claimed that it carried out the attack, saying in a statement that its fighters had fired six mortar shells.
Morag, which lies to the north of the southern Palestinian town of Rafah, is one of 21 Gaza settlements which are due to be dismantled next year as part of Prime Minister Ariel Sharon's controversial disengagement plan.
Dozens of Palestinian children
have suffered serious injuries
Meanwhile, medics carrying out an autopsy on 13-year-old Iman al-Hams found five bullets in her head and 15 bullets throughout the rest of her body.
Shot while walking to school on 5 October, Israeli troops also prevented paramedics from giving her immediate medical attention.
Some five Israeli children have died in the same period. Three were killed in an attack on a hotel in Egypt and two others died in a Qassam rocket attack on an illegal settlement.
Aram's death raises the overall toll since the September 2000 start of the al-Aqsa intifada to 4535 men, women and children.
Around 80% of those killed have been Palestinian.