Islam Times reports from BBC: On Friday, Yingluck won the support of 296 members of the lower house of parliament, while three members voted against her and 197 abstained.
King Bhumibol Adulyadej is expected to endorse the new premier in a ceremony in the next few days.
“People will judge whether my work satisfies them and meets their expectations or not,” Yingluck said after the vote.
Her Pheu Thai party won the parliamentary election on July 3, and, along with its coalition partners, now commands a huge majority in the lower house.
Her brother Thaksin Shinawatra was deposed as prime minister in a military coup in 2006. He has been living in Dubai ever since.
Thaksin's populist policies won him massive support among the rural and urban poor. He is still extremely popular, and numerous demonstrations have been held calling for his return to power.
In 2010, thousands of pro-Thaksin protesters occupied parts of Bangkok for months. Dozens of people were killed in the army's operation to restore order.
Political analysts say Yingluck will struggle to convince her critics that she can be a strong leader in her own right.
Although Pheu Thai won a clear majority of seats in parliament, Yingluck said her party would form a coalition with four other parties “to work together to run the country and solve people's problems.”