A greeting card is an illustrated, folded card featuring an expression of friendship or other sentiment. Although greeting cards are usually given on special occasions, such as birthdays, Christmas or other holidays, they are also sent to convey thanks or express other feeling. Greeting cards, usually packaged with an envelope, come in a variety of styles. There are both mass-produced as well as handmade versions that are distributed by hundreds of companies large and small. While typically inexpensive, more elaborate cards with die-cuts or glued-on decorations may cost up to US $5 each.

Hallmark Cards and American Greetings are the largest producers of greeting cards in the world. Recycled Paper Greetings was the first to print their product on recycled paper, a practice much more common today. In the United Kingdom, it is estimated that one billion pounds are spent on greeting cards every year, with the average person sending 55 cards per year.

In western countries and increasingly in other societies, many people traditionally mail seasonally themed cards to their friends and relatives in December. Many service businesses also send cards to their customers in this season, usually with a universally acceptable non-religious message such as "happy holidays" or "seasons's greetings".

The Greeting Card Association is an international trade organization representing the interests of greeting card and stationery manufacturers. John Beeder, former president of the Greeting Card Association, says greeting cards are effective tools to communicate important feelings to people you care about: "Anyone feels great when they receive an unexpected card in the mail. For me, there’s nothing like a greeting card to send a special message. I’m proud to be a part of an industry that not only keeps people connected, but uses both imagery and the power of words to help us express our emotions.”