The Thanyaburi Provincial Court has sentenced Move Forward Party MP Chonthicha Jangrew to two years in prison for royal defamation under Section 112 of the Criminal Code.
The court's ruling, read out on Monday morning, handed her a three-year sentence, but then reduced it to two years with no suspension.
Another charge of violating the emergency decree on public gatherings was dropped, according to the court.
The charges were filed after she and nine other activists rallied in front of the court in Thanyaburi district in Pathum Thani on Sept 11, 2021, demanding the release of political prisoners.
Ms Chonthich had immediately applied for and was then allowed release on bail to fight the case in the Appeal Court, according to Thai Lawyers for Human Rights.
She retains her MP status during the court battle.
Move Forward leader Chaithawat Tulathon said before entering the court building that he hoped the court would allow bail if she was found guilty.
Ms Chonthicha is one of three MPs of the main opposition party facing lese majeste charges.
Bangkok MP Rukchanok Srinork was sentenced in December 2023 to six years in prison, without suspension, for lese-majeste and computer crime in connection with online comments she made between July 18 and Aug 9, 2021. She is currently free on bail while she appeals.
Bangkok MP Piyarat “Toto” Jongthep faces three charges under Section 112 in connection with his activities as a leader of the WeVo guards during the anti-government protests in 2020 and 2021.