"The Bamboo Trunk" explores the difficulties facing Asians in the oil-rich region through the story of Jose, a young man rejected by the family of his Kuwaiti father because his mother was a Filipina maid.
"This novel is aimed at the young people of the Gulf," said Sanaussi, 32.
"We do not listen to the others. We do not see them, and we have a hostile attitude towards them," he told reporters after the result announcement late on Tuesday.
There are millions of South Asian workers in the Gulf region, including an army of domestic staff.
Sanaussi said he felt a "sense of guilt" towards foreign workers after he got to know many of them while working as a manager at a factory.
That experience was the spur to write the book, he said.
The winner of the International Prize of Arab Fiction, which is managed in association with London's Man Booker Prize and supported by the Emirates Foundation, receives $50,000, while the six shortlisted authors get $10,000 each.