Disclosed are blanks for divider shelves for erecting into load-bearing divider shelves for use in cartons. In one embodiment, a divider blank for erecting into a load-bearing divider shelf having a length and width is disclosed. The divider blank comprises two center supports that are foldably attached by a fold line extending in a lengthwise direction. Each center support has two ends in which each end is foldably attached to an end support. Each end support has a top and bottom and is attached to an angular slot flap by a fold line extending between the top and bottom of the end support. Each angular slot flap has a locking slot in the mid-section between the top and bottom of the flap. The divider shelves erected from the blanks and the carton with the divider shelves installed are also disclosed.