A walker (North American English) or walking frame (British English) is a device that gives support to maintain balance or stability while walking, most commonly due to age-related mobility disability, including frailty. Another common equivalent term for a walker is a Zimmer (frame), a genericised trademark from Zimmer Biomet, a major manufacturer of such devices and joint replacement parts. Walking frames have two front wheels, and there are also wheeled walkers available having three or four wheels, also known as rollators.

Walkers started appearing in the early 1950s. The first US patent was awarded in 1953 to William Cribbes Robb, of Stretford, UK, for a device called "walking aid", which had been filed with the British patent office in August 1949. Two variants with wheels were both awarded US patents in May 1957, and the first non-wheeled design that was called a "walker" was patented in 1965 by Elmer F. Ries of Cincinnati, Ohio. The first walker to resemble modern walkers was patented in 1970 by Alfred A. Smith of Van Nuys, California.