Mahou Sensei Negima [Manga]

A ten-year-old wizard, aspires to become a “Magister Magi”, a special wizard who, under the guise of working under a Non-Goverment-Organization, uses his powers to help normal people. After graduating from the Merdiana Magic Academy in Wales, he is assigned the task of teaching English at Mahora Academy’s middle school, where his homeroom class consists of 31 girls, each very special in her own way. The series details his time and adventures in Japan as he gains acceptance and respect from his students, helps them in their problems, and faces magical threats from inside and outside Mahora Academy. (From: Wikipedia)