A playing card is a piece of specially prepared card stock, heavy paper, thin cardboard, plastic-coated paper, cotton-paper blend, or thin plastic that is marked with distinguishing motifs. Often the front (face) and back of each card has a finish to make handling easier. They are most commonly used for playing card games, and are also used in magic tricks, cardistry, card throwing, and card houses; cards may also be collected. Some patterns of Tarot playing card are also used for divination, although bespoke cards for this use are more common. Playing cards are typically palm-sized for convenient handling, and usually are sold together in a set as a deck of cards or pack of cards.

The most common type of playing card in the West is the French-suited, standard 52-card pack, of which the most widespread design is the English pattern, followed by the Belgian-Genoese pattern. However, many countries use other, traditional types of playing card, including those that are German, Italian, Spanish and Swiss-suited. Tarot cards (also known locally as Tarocks or tarocchi) are an old genre of playing card that is still very popular in France, central and Eastern Europe and Italy. Asia, too, has regional cards such as the Japanese hanafuda. The reverse side of the card is often covered with a pattern that will make it difficult for players to look through the translucent material to read other people's cards or to identify cards by minor scratches or marks on their backs.

Playing cards are available in a wide variety of styles, as decks may be custom-produced for competitions, casinos and magicians (sometimes in the form of trick decks), made as promotional items, or intended as souvenirs, artistic works, educational tools, or branded accessories. Decks of cards or even single cards are also collected as a hobby or for monetary value. Cards may also be produced for trading card sets or collectible card games, or as supplements for board games, however these are not generally regarded as playing cards.