The NATO Codification System (NCS) is a uniform and common system for identification, classification and stock numbering of Items of Supply of user nations. It is designed to achieve maximum effectiveness in logistics support and to facilitate materiel data management. The System has been agreed by all signatories of the Alliance and sponsored non-NATO countries for use in identifying equipment and supplies

The principal document of the System is the Allied Codification Publication No 1 (ACodP-1), also known as the NATO Manual on Codification, which describes the system operating procedures. In its military application the System has been accepted under two NATO Standardisation Agreements (STANAGs) - STANAG 3150 (Uniform System of Supply Classification) and STANAG 3151 (Uniform System of Item of Supply Identification). The System, which is based upon the United States Federal Catalogue System, is also used by the Civil Departments of some NATO nations. It is governed by the NATO Group of National Directors on Codification (AC/135) and implemented by the National Codification Bureau (NCB) of each user nation.