STORY: Most of the dead were members of the Abu Rayya family, their bodies wrapped in Palestinian flags and brought into a mosque for prayers before being buried at the Cemetery of Martyrs east of the Jabalia refugee camp.
The Islamist Hamas group, which has ruled the Gaza Strip since 2007, gave the victims a military funeral.
It took firefighters more than an hour to get control of the massive flames that burst through the top floor of a four-story residential building in Jabalia, one of eight refugee camps in the Gaza Strip, where 2.3 million people live in one of the most densely populated areas on earth.
Details about how or why the fire broke remain unclear as there were no survivors, Abu Ahmad Abu Rayya, the head of the clan, said.
Gaza's Interior Ministry said it had launched an investigation into the incident which revealed that large amounts of gasoline had been stored at the site, possibly fuelling the blaze that quickly engulfed the building.
Palestinian President Mahmoud Abbas called it a national tragedy and declared Friday a day of mourning.