She says Maryland's schools have received the top ranking by Education Week magazine three years in a row, and that it's a good time to pass the job on to someone else.
Grasmick is Maryland's first female superintendent. She began her career as a teacher of deaf children in Baltimore.
In 1989 she was appointed the Maryland special secretary for Children, Youth and Families, and in 1991 Maryland's State Board of Education appointed her superintendent.
Grasmick will retire on June 30.