An absorbent article for pets includes a top sheet, a back surface layer, an absorbent core, a first end portion, a second end portion, and a pair of side portions. Such absorbent articles for pets are stacked and packaged while each absorbent article is folded and the portion of the back surface layer which is near the first end portion forms a first outer surface. The absorbent article for pets also includes: a hook member provided on the portion of the back surface layer which is near the first end portion; an engaging section provided on the portion of the top sheet which is near the second end portion and engageable with the hook member; and a weak engagement section provided at a position at which the weak engagement section is in contact with the hook member of an adjacent absorbent article of the stacked absorbent articles for pets.