The bright 16-year-old British International School student sealed the title in Bangkok last night.
She was also selected as Most Popular Media choice.
The young beauty pockets 300,000 baht.
Candidates from all over Thailand competed for the prestigious title. Tera was among those who gathered on Phuket at the Kata Beach Resort on September 30.
In a triumph for Phuket's international mix, her father is Thai and her mother is South African.
Tia's Facebook update today: ''I gots me a crown bitches!''