It was not immediately clear at what point during the flight the injuries and death occurred.
Thai media reports said 30 people were injured, while Singapore Airlines did not specify how many people were injured.
Video clips shared on social media by reporters at the scene showed emergency vehicles lining up at the airport.
Bangkok’s Suvarnabhumi Airport official confirmed one death but could not confirm the total number of injured.
The Boeing 777-300ER plane carrying 211 passengers and 18 crew members was en route to Singapore when it made the emergency landing, the airline said in a statement.
“Our priority is to provide all possible assistance to all passengers and crew on board the aircraft,” the airline said.
“We are working with local authorities in Thailand to provide the necessary medical assistance.”
Singapore Airlines’ last fatalities were in October 2000, when a plane crashed on a closed runway during takeoff from Taiwan, killing 83 people.
Singapore Airlines has had seven accidents, according to data from the Aviation Safety Network.
Thai immigration police said medical personnel boarded the plane to assess injuries but could not confirm the number and some uninjured passengers were deplaned.
