No, it doesn't matter. Taking the vitamins with a meal can help with absorption, so they do not get expelled as urine too quickly, so do you take them with dinner or several hours afterwards? having fat with the vitamins helps with fat-soluble vitamins like A and D, ( again the meal helps here ), so the fish oil you take at the same time should help as well. I have not seen any studies or research that showed the time of day mattered at all for vitamin intake