A suitcase is a form of baggage. It is a rectangular container with a handle and is typically used to carry one's clothes and other belongings while traveling. The first suitcases appeared in the late 19th century due to the increased popularity of mass tourism at the time, and were meant to hold dress suits (hence their name). They were originally made using heavier materials such as leather or steel, but, beginning in the 1930s, were constructed with more lightweight materials like plastic and cardboard.

Before the 1970s, the idea of rolling luggage was shunned by the travel industry, who viewed it as much less masculine than traditional luggage. American entrepreneur Bernard Sadow pitched his version of the wheeled suitcase, for which he was granted a patent in 1972, to various department stores before it was picked up and sold at Macy's stores starting in 1970. It took several years to become the predominant form of suitcase, and Sadow's version was soon superseded by the Rollaboard, a type of wheeled suitcase that was upright rather than flat like Sadow's model and invented in 1987 by American pilot Robert Plath. The addition of wheels to the suitcase has since been called one of the most significant innovations in travel.

Smart suitcases with enhanced capabilities such as GPS tracking and device charging were popularized in the 2010s, though explosions of their lithium ion batteries in cargo holds caused them to be banned from being checked by many major airlines in the late 2010s.

During the Crusades, the first luggage—wheeled containers used to transport weaponry—was developed in 1153. The word "luggage", derived from the verb "lug", was added to the Oxford English Dictionary in 1596 to mean "denoting inconveniently heavy baggage". Luggage prior to the invention of the suitcase was mostly wood and leather trunks with an iron base, which were waterproofed using canvas or tree sap. Servants were often made to carry these trunks for their owners, such as for European elites during the Grand Tour in the 18th century, since travel was mostly exclusive to the wealthy.

As mass tourism increased in popularity and travel became accessible to non-elites due to railways and cruise ships, the need for more practical luggage increased. In the late 19th century, the first luggage known as "suit cases" or "suit-cases", which were meant to carry dress suits without wrinkling them, came about. Other terms used include "grip" or "gripsack", especially for small luggage. The earliest models of suitcases were invented by British businessmen, who used them to carry goods and clothing. They were modeled after trunks and made by stretching leather, rubbery cloth, or wicker over a flat, rigid frame made of wood or steel with leather or brass caps on the corners and a handle on their long side, contrasting them with trunks, which had handles on their two shorter sides. They typically had a compartment for shirts and a hat box on the inside. Suitcases first started being manufactured alongside trunks by luggage companies such as the Shwayder Trunk Manufacturing Company, which would later be renamed Samsonite. They were initially considered a lesser alternative to trunks, as evidenced by North American travel catalogs from the turn of the 20th century advertising trunks much more prominently than suitcases.

Lightweight suitcases were mostly marketed at first toward women. In 1938, a weight limit of 40 pounds for checked bags was established in the United States, which led to the heavier leather model of suitcase being supplanted by lighter plastic and cardboard suitcases throughout the 1930s and 1940s. German luggage company Rimowa built the first aluminum suitcase, which it started selling in 1950 with a grooved design inspired by the Junkers Ju 52 airplane. In Europe, porters were responsible for carrying train passengers' suitcases until around the middle of the 20th century, when they became less abundant.

Early patents for a wheeled trunk and a wheeled suitcase came in 1887 and 1945, respectively, and a design for a "portable porter", a wheeled device that could be attached to a suitcase, was advertised in British newspapers in the 1940s. However, none of these designs originally caught on. During her second world tour in 1928, American artist Anita Willets-Burnham made the first recorded wheeled suitcase, which had two baby carriage wheels attached to it and a telescoping wooden handle. Until the 1970s, wheeled luggage was seen by the travel industry as a niche invention solely for women.

In 1970, Bernard D. Sadow, the then-vice president of Massachusetts luggage company U.S. Luggage, was carrying two heavy 27-inch suitcases at an airport in Puerto Rico on his way back from a family vacation in Aruba when he noticed a worker rolling a heavy machine on a wheeled platform. After remarking to his wife that people needed wheels for their luggage, Sadow returned to his factory in Fall River, Massachusetts and attached casters to a suitcase with a strap that allowed him to tow it behind him. Sadow spent months attempting to sell his wheeled suitcase to various New York City department stores, but was met with resistance. Most department stores, according to him, refused to sell his invention due to a "macho feeling" that men would consider rolling their luggage "wimpy" and that women who travelled would have their husbands around to carry their suitcases for them.