Articles of footwear, including athletic footwear, may include: (a) an upper including an opening through which a leg of a wearer extends, wherein the upper includes a foot insertion opening extending rearwardly and downwardly from a front portion of the leg opening at least to a heel area of the upper; (b) a closure system for releasably closing the foot insertion opening and optionally tightening the shoe on the foot; and (c) a sole structure engaged with the upper. The foot insertion opening widely opens the side and/or rear area of the shoe to allow for easy insertion and removal of a foot. Such uppers can be particularly useful for hightop athletic footwear, boots, or other footwear that extends up to or at least partially over a wearer's ankles.