Lumberjack is a mostly North American term for workers in the logging industry who perform the initial harvesting and transport of trees. The term usually refers to loggers in the era before 1945 in the United States, when trees were felled using hand tools and dragged by oxen to rivers.

The work was difficult, dangerous, intermittent, low-paying, and involved living in primitive conditions. However, the men built a traditional culture that celebrated strength, masculinity, confrontation with danger, and resistance to modernization.

The term lumberjack is of Canadian derivation. The first attested use of the term combining its two components comes from an 1831 letter to the Cobourg, Ontario, Star and General Advertiser in the following passage: "my misfortunes have been brought upon me chiefly by an incorrigible, though perhaps useful, race of mortals called lumberjacks, whom, however, I would name the Cossacks of Upper Canada, who, having been reared among the oaks and pines of the wild forest, have never been subjected to the salutary restraint of laws."

The term lumberjack is primarily historical, and of colloquial contemporary usage; logger is commonly used by workers in the 21st century. When lumberjack is used, it usually refers to a logger from an earlier time before the advent of chainsaws, feller-bunchers and other modern logging equipment. Other terms for the occupation include woodcutter, shanty boy and the regional woodhick of Pennsylvania, United States.^{[citation needed]} In Australia, the occupation is referred to as timber cutter or cool cutters.

A logger employed in driving logs down a river was known locally in northern North America as a river pig, river hog, river rat, or catty-man. The term lumberjill has been used for a woman lumberjack; for example, the Women's Timber Corps in Britain during World War II.

Lumberjacks worked in lumber camps and often lived a migratory life, following timber harvesting jobs as they opened. Being a lumberjack was seasonal work. Lumberjacks were exclusively men. They usually lived in bunkhouses or tents. Common equipment included the axe and cross-cut saw. Lumberjacks could be found wherever there were vast forests to be harvested and a demand for wood, most likely in Scandinavia, Canada, and parts of the United States. In the U.S., many lumberjacks were of Scandinavian ancestry, continuing the family tradition. American lumberjacks were first centred in north-eastern states such as Maine. They then followed the general westward migration on the continent to the Upper Midwest, and finally the Pacific Northwest. Stewart Holbrook documented the emergence and westward migration of the classic American lumberjack in his first book, Holy Old Mackinaw: A Natural History of the American Lumberjack. He often wrote colourfully about lumberjacks in his subsequent books, romanticizing them as hard-drinking, hard-working men. Logging camps were slowly phased out between World War II and the early 1960s as crews could by then be transported to remote logging sites in motor vehicles.

Despite the common perception that all loggers cut trees, the actual felling and bucking of trees were specialized job positions done by fallers and buckers. Faller and bucker were once two separate job titles, but they are now combined.

The natural division of labour in lumber camps led to other specialized jobs on logging crews, such as whistle punk, high climber, and chaser. The whistle punk's job was to sound a whistle (usually at the Steam donkey) as a signal to the yarder operator controlling the movement of logs. He also had to act as a safety lookout. A good whistle punk had to be alert and think fast as others' safety depended on him. The high climber (also known as a tree topper) established a spar tree so logs could be skidded into the landing. Using tree climbing gaffs and rope to ascend a tall tree in the landing area of the logging site, he would chop off limbs as he climbed, chop off the top of the tree, then attach pulleys and rigging to the tree for the yarder. High climbers and whistle punks began to be phased out in the 1960s to early 1970s when portable steel towers began to replace spar trees and radio equipment supplemented whistles for communication. The choker setters attached steel cables (or chokers) to downed logs so they could be dragged into the landing by the yarder, and still do today. The chasers remove the chokers once the logs are at the landing. Choker setters and chasers are often entry-level positions on logging crews, with more experienced loggers seeking to move up to more skill-intensive positions such as yarder operator or supervisory positions such as hook tender.