Flexible working hours refers to the practice by employers of allowing employees to vary their attendance pattern. Variation is usually in terms of start and finish times, as well as hours per day. Flexible working hours are often referred to as flexitime. Employees working flexible hours are able to use flexitime credit to take time off without reducing other leave credits. Flexible working hours are usually subject to a number of operating rules.

From a transport perspective, flexible working hours are introduced to spread travel demand beyond conventional peak hours and thus, reduce congestion and/or to facilitate alternatives to solo commuting, which in turn reduces congestion. Flexible hours facilitate ride sharing, cycling and public transport use. From a business perspective, the ultimate aim is to increase efficiency through reduced congestion.

Demand impacts can be moderate, but relatively stable over time, with obvious consequences for the nature of contribution to key policy objectives.