• Fixed Mobile Substitution
• Flying Model Simulator, a free personal computer flight simulator application for radio-controlled aircraft
• Foreign military sales, a term in arms trade
• Final Multiple Score, the calculation used to advance enlisted sailors in the United States Navy.
• Fisichella Motor Sport, motor racing team owned by F1 driver Giancarlo Fisichella.

Government agencies

• Federal Magistrates Service, the former name of the Federal Magistrates' Court of Australia
• Federated Malay States (1895–1946) (Negeri-negeri Melayu Bersekutu), historical British protectorate in then British Malaya
• Financial Management Service, a bureau of the U.S. Treasury Department
• Fiji Meteorological Service, the central weather office of Fiji
• Federal Migration Service of Russia (Федеральная миграционная служба России)

Operations

• Facilities Management System
• Fleet Management System
• Flexible Modeling System, developed at the Geophysical Fluid Dynamics Laboratory
• Flight management system
• Flexible manufacturing system, production system using computer-controlled machines that can adapt to various versions of the same operation
• Flexible Monitoring System, as in Pandora FMS

People

• Fratres Maristae a Scolis, post-nominal letters for the catholic religious order of the Marist Brothers

Educational Institutions

• Florida Military School
• Faculty of Management Studies, Delhi
• Fugett Middle School, a middle school in West Chester, Pennsylvania.

Medicine

• False memory syndrome
• Fibromyalgia Syndrome

Computing

• File Management System, part of Atari DOS
• FMSLogo, a free Microsoft Windows based Logo (formerly MSWLogo)
• Fortran Monitor System
• Flash Media Server
• Freenet Message System

Simulation and Training

• Full Mission Simulator, a simulator designed to train for the full operation mission, generally in the military. Frequently an FMS will have a large database both geographically and in terms of other 'entities' in the simulation such as friendly and enemy forces and their weapons