Abstract: The invention relates to a fiber optic telecommunications module (100) comprising: a main housing portion (102) including a top wall (108), a bottom wall (110), a first transverse sidewall (106), a rear wall (112), an open front end (120), and an open second side (116), the main housing portion (102) including an optical component (130); a cover portion (104, 104a) coupled to the main housing portion (102) to close up the open second side (116) of the main housing portion (102) and keep the optical component (130) within the main housing portion (102); a first fiber optic adapter module (316) and a second fiber optic adapter module (316) removably coupled to the main housing portion (102) to close the open front end (120) of the main housing portion (102), the first and second fiber optic adapter modules (316) being provided in a stacked arrangement in a direction extending from the first transverse (106) sidewall toward the cover portion (104, 104a); wherein each of the first and second fiber optic adapter m