Hallmark Cards, a privately owned company based in Kansas City, Missouri, is the largest manufacturer of greeting cards in the United States. Some 50% of greeting cards sent in the United States every year is manufactured by Hallmark.

Founded in 1910 by 18-year-old Joyce Hall selling postcards, by 1915 the company was known as Hall Brothers and sold valentines and Christmas cards, and in 1917, Hall and his brother, Rollie, invented modern wrapping paper when they ran out of traditional colored tissue paper.

In 1928, the company adopted the brand name "Hallmark", after the symbol used by goldsmiths in London in the 14th century, and began printing its name on the back of every card and promoting it in ad campaigns, a practice the company continues to the present day. In 1944, it adopted its current slogan, "When you care to send the very best." In 1954, it changed its name from Hall Brothers to Hallmark.

In 1951, Hall sponsored a television program for NBC that gave rise to the Hallmark Hall of Fame, which has won 78 Emmy Awards.

Hallmark owns Hallmark Entertainment, a producer of television shows and mini-series; the Hallmark Channel television network; Binney & Smith, makers of Crayola-brand crayons, and operates a chain of independently-owned card and gift stores in the United States.