According to the 18th volume of manga Junjou Romantica, a third season of the anime has been decided. More information will be announced at a later time.
Junjou Romantica began airing on April 11, 2008 to June 27, 2008. The second season titled Junjou Romantica 2 began airing on October 12, 2008 to December 28, 2008. An OVA titled Junjou Romantica OVA was released around Christmas 2012.
Junjou Romantica synopsis from Haruhichan:
Three very different couples caught up in a storm of pure romance!
Romantica: Misaki is struggling to prepare for his college entrance exams, so his brother arranges for a private tutor. But Misaki’s nightmare is just beginning when his tutor, Usami, comes on to him! How will Misaki ever manage to pass his exam? And why does he feel so mysteriously drawn to Usami?
Egoist: Just when Kamijou’s life is at its lowest, he has a chance meeting with a man who never lets anything hold him back: Nowaki. His name means “typhoon,” and he’s about to take Kamijou on a whirlwind ride that will turn everything upside-down.
Terrorist: Miyagi always seems to shrug off the cares of the world with a joke and a smile, but even he has problems, although he doesn’t let them show. Foremost is Shinobu, a relentless young man who’s adamant that they’re destined to be together.
Source: @mtnk1419’s Twitter