Doki Doki School Hours (せんせいのお時間 Sensei no Ojikan) is a 2004 anime series and 2005 OAV series based on the manga by Tamami Momose. Both series were dubbed and released in 2005 by Geneon Entertainment.
Synopsis
Meet Suzuki Mika, teacher at Okitsu High School. Mika-sensei is a good teacher, but she has a small problem... literally. Although she's 27, she is only 148 cm tall, and has the face of a child. As a result, it is often difficult for Mika-sensei to get anyone to take her seriously.