The boy in northeastern Kratie province fell ill after eating poultry with his family, suffering fever, coughing and breathing difficulties before dying on Thursday.
The ministry said tests confirmed the boy died from the highly pathogenic H5N1 strain of the virus.
"According to the evidence, five chickens and three ducks had died at the patient's home, and they cooked the chickens and ducks for food to eat," the ministry said in a statement.
It said health officials were investigating the source of the virus and searching for more cases.
"The ministry of health again reminds all people to be vigilant about bird flu because H5N1 continues to threaten the health of our people," the statement added.
At least three people, including a two-year-old girl, died from bird flu in the kingdom last year
Since late 2021, Europe has been hit by its worst-ever outbreak of bird flu, with North and South America also experiencing severe outbreaks.
This has led to the culling of tens of millions of domestic poultry worldwide, many with the H5N1 strain, including 140,000 in the Czech Republic earlier this month.
The global outbreak is also responsible for the deaths of tens of thousands of wild birds.