Thousands of mourners are expected to attend the funeral of renegade Thai general Khattiya Sawasdipol, who was shot in May as he backed anti-government protesters in Bangkok.
Some 1,000 police are being deployed in the capital, although police say they do not expect trouble.
Maj Gen Khattiya, known as Seh Daeng (Commander Red), was shot by an unknown gunman as he spoke to a US journalist.
Eighty-eight people died during the bitter nine-week political protest.
The demonstrators, known as red-shirts, occupied large parts of Bangkok. They demanded early elections, claiming that the current government came to power illegally.
More than 1,000 people were injured in the bloody confrontation, which ended when troops entered the protesters’ heavily-fortified camp.
The government remains in place and several red-shirt leaders are in detention.