A process for producing ZSM-48 comprises crystallizing an aqueous reaction mixture comprising at least one source of silica, at least one source of alumina, at least one source of hydroxyl ions, at least one source of diquaternary alkylammonium, R2+, ions having the formula:(CH3)3N+(CH2)5N+(CH3)3 and optionally ZSM-48 seed crystals, wherein said reaction mixture has a composition including the following molar ratios: