Spokesman of the Ministry of Health Rungrueng Kitphati said the death was a 86-year-old woman from the southern province of Songkhla.
Thailand detected its first Omicron case last month that led to the reinstatement of its mandatory COVID-19 quarantine for foreign visitors.
The country has so far reported over 10,000 cases of the Omicron variant, the spokesman said.
Since the pandemic started in 2020, Thailand has logged more than 2.3 million COVID-19 cases, with nearly 22,000 deaths. On January 16, the country recorded 8,077 new infections and nine deaths.
About 66 percent of an estimated 72 million living in Thailand have received two doses of COVID-19 vaccines, and nearly 15 percent have received booster shots./.