A time and motion study (or time-motion study) is a business efficiency technique combining the Time Study work of Frederick Winslow Taylor with the Motion Study work of Frank and Lillian Gilbreth (best known through the biographical 1950 film and book Cheaper by the Dozen). It is a major part of Scientific management (Taylorism).

A time and motion study would be used to reduce the number of motions in performing a task in order to increase productivity. The best known experiment involved bricklaying. Through carefully scrutinising a bricklayer's job, Frank Gilbreth reduced the number of motions in laying a brick from 18 to about 5. Hence the bricklayer both increased productivity and decreased fatigue.

The Gilbreths developed what they called therbligs ("therblig" being "Gilbreth" spelled backwards, with a slight variation), a classification scheme comprising 17 basic hand motions.