Tens of thousands took to the streets at the height of the protests, many making unprecedented public criticism of the royal family as well as demands for transparency and reform.
More than 270 people were charged with lese-majeste after those protests, including two elected MPs.
New York-based Human Rights Watch (HRW) says the lese-majeste law has been routinely used to silence political dissent.
Thai authorities prosecuted at least 258 people last year on lese-majeste charges in relation to activities undertaken at democracy protests or comments made on social media, HRW said in its 2024 World Report.
Thailand, Southeast Asia’s second-largest economy, is known for its chronic instability, with a dozen coups since the end of absolute monarchy in 1932.