"Hallmark holiday" is a disparaging term, used predominantly in the United States, to describe a holiday that exists primarily for commercial purposes, rather than to commemorate a traditionally significant religious or secular event. The name comes from Hallmark Cards, a privately owned American company based in Kansas City, Missouri, that presumably benefits from such manufactured events through sales of greeting cards and other items. The company itself denies having any role in the creation of the holidays that bear this moniker. Holidays that have been referred to as "Hallmark Holidays" include Valentine's Day, Mother's Day , Fathers' Day , Sweetest Day , Christmas in July, and Boss's Day.

Another connotation of the term "Hallmark Holiday" is that of an ideal, perfect holiday. On such occasions, as depicted in Hallmark Cards (and other media) advertising, one is surrounded by loving family and friends, there is a strong sense of camaraderie and fun, and no problems surface to disrupt the conviviality and serenity of the day.

Related to "Hallmark Holiday" is the pop-culture term "Hallmark Moment." This is a point in time when one experiences a serendipitous event or encounter. It is a perfect moment, when all expectations are met or exceeded.