A standard operating procedure (SOP) is a set of step-by-step instructions compiled by an organization to help workers carry out routine operations. SOPs aim to achieve efficiency, quality output, and uniformity of performance, while reducing miscommunication and failure to comply with industry regulations.

Some military services (e.g., in the U.S. and the UK) use the term standing operating procedure, since a military SOP refers to a unit's unique procedures, which are not necessarily standard to another unit. The word "standard" could suggest that only one (standard) procedure is to be used across all units.

The term is sometimes used facetiously to refer to practices that are unconstructive, yet the norm. In the Philippines, for instance, "SOP" is the term for pervasive corruption within the government and its institutions.