The 11th volume of Robico's Tonari no Kaibutsu-kun manga confirmed on Friday that the series will end in the next volume. The 12th volume of the shōjo romance will bundle an original anime DVD when it ships this summer.
The manga centers around Shizuku Mizutani, a girl who has absolutely no interests except for school and her plans for the future. A boy named Haru Yoshida would be seated next to her in class, but he has been constantly absent since the first day of school. By chance, she is sent to deliver class printouts to him, and that leads Yoshida to believe they are friends.
The manga has running in Kodansha's Dessert magazine since 2008, and inspired a television anime series that ran last year. Crunchyroll streamed the show under the title My Little Monster.
Source : http://www.animenewsnetwork.com/news/2013-01-12/tonari-no-k aibutsu-kun-manga-to-end-in-12th-volume