The army seized power from the civilian government in 2014, saying it was forced to act to end bloody street protests and rampant corruption.
The army, navy and air force will receive a two per cent raise taking next year's spending to 210.7 billion baht (nearly USD 6.1 billion), according to the budget endorsed by the hand-picked National Legislative Assembly.
The budget comes into effect next month and runs until September 2017.
It is the third straight year of rises in state spending for defence since the coup.
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Each coup has broadly been followed by a handsome budget hike, while the civilian leaders who have governed intermittently have also lavished cash on the powerful military hoping to curry favour.
The budget for education was given a 4.7 per cent haircut to 493 billion baht (USD 14.1 billion) and transport was cut by two thirds from USD 136 billion baht to USD 63.5 billion.
"This budget will be spent based on laws and rules to maintain the country's fiscal discipline," Wisanu Krea-Ngam, deputy prime Minister, said in televised comments at the end of the vote, promising the budget allocation had been carefully considered.
"Perhaps the rise does not appear to be breathtaking but the amount of spending is remarkable -- really more than ever before," said Paul Chambers a Thailand-based expert on the military, adding it was unclear how the spending had been justified.
After years of impressive growth, Thailand's economy is faltering, mired in high household debt, stuttering exports and low consumer confidence.
The army's influence in Thai politics has been embedded in a new constitution written by junta appointees.