The 36 cabinet ministers including the prime minister were sworn in during an audience with the king and queen at Dusit Palace.
The new government pledged their loyalty to the monarchy.
"I hope the cabinet and the government will have encouragement and power to perform their duty well and do what is right," Thai King Maha Vajiralongkorn said.
The new government has yet to officially perform until the government policy debate, which was scheduled from July 25 to July 27 at the parliament, is finished.
"We have to prepare for the next task that is to present the government policies and create a sense of unity for the country, religion, king, and all of us, the people," Prayuth told reporters after Tuesday's ceremony.
"Many people have high hope for this government."
