The hacker, known by the pseudonym "AriP_ReCA", left a message on the Thai Cabinet Secretariat's website, a source of information on Thai government policy where he also thanked fellow hackers, according to media reports.
"DeFace by AriP_ReCA, InDoneSian NeWbie TouCh YouR SySTeM, Dedicated to My Girl Friend Ermi, I LOVE YOU," the touching message said.
"I don't know why he hacked into the website," Cabinet secretary-general Borwornsak Uwanno told Thai daily The Nation. "It contained nothing classified or related to national security."
Thailand is currently considering legislation that would make hacking into websites illegal.