"Fanboys" writer-director Kyle Newman is to direct the movie, which was written by John D'Arco.
Principal photography is to begin this fall.
"Barely Lethal" is being produced by RKO Pictures with Hopscotch Pictures and Brett Ratner's Rat Entertainment. In it, Steinfeld will play a 16-year old international assassin who fakes her own death and enrolls in a suburban high school while yearning for "normal" adolescence, a synopsis said.
Jackson will play the former employer who tries to get her back to work.