''Walk redirects here. That term may also refer to a base on balls in baseball or walking (basketball).

Walking is the main form of animal locomotion on land, distinguished from running and crawling. When executed in shallow water, it is usually described as wading and when executed vertically it becomes scrambling or climbing. The word walking is derived from the Old English walcan (to roll).

Walking is generally distinguished from running in that only one foot at a time leaves contact with the ground: for humans and other bipeds running begins when both feet are off the ground with each step. (This distinction has the status of a formal requirement in competitive walking events, often resulting in disqualification even at the Olympic level.) For horses and other quadrupedal species, the running gaits may be numerous, and walking keeps three feet at a time on the ground.