No Its not...
Thailand is not a third world country, but rather an upper-middle income economy. It's considered a developing country that's making progress towards becoming more developed.
Thailand has a growing economy and is considered a middle power in global affairs.
It's a founding member of ASEAN and has the second-largest economy in Southeast Asia.
Thailand's income per capita has increased, and its poverty rate has decreased.
It's considered a newly industrialized economy, with manufacturing, agriculture, and tourism as leading sectors.
Thailand is making progress towards meeting the Sustainable Development Goals.
However, some say that Thailand has pockets of poverty, and that the country's structural transformation has stalled since the mid-2010s.